This article lists

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

s by their classification in the

International Union of Biochemistry and Molecular Biology The International Union of Biochemistry and Molecular Biology (IUBMB) is an international non-governmental organisation concerned with biochemistry and molecular biology. Formed in 1955 as the International Union of Biochemistry (IUB), the union ...

's Enzyme Commission (EC) numbering system. *

List of EC numbers (EC 5) This list contains a list of EC numbers for the fifth group, EC 5, isomerases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. All official information is tab ...

List of EC numbers (EC 6) This list contains a list of EC numbers for the sixth group, EC 6, ligases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. All official information is tabulat ...

:Oxidoreductases (EC 1) (
Oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually u ...
)

Dehydrogenase A dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN. Like all catalysts, they catalyze reverse as well as ...

* Luciferase *

DMSO reductase DMSO reductase is a molybdenum-containing enzyme that catalyzes reduction of dimethyl sulfoxide (DMSO) to dimethyl sulfide (DMS). This enzyme serves as the terminal reductase under anaerobic conditions in some bacteria, with DMSO being the ter ...

:EC 1.1 (act on the CH-OH group of donors)

* :EC 1.1.1 (with NAD⁺ or NADP⁺ as acceptor) ** Alcohol dehydrogenase (NAD) ** Alcohol dehydrogenase (NADP) **

Homoserine dehydrogenase In enzymology, a homoserine dehydrogenase () is an enzyme that catalyzes the chemical reaction :L-homoserine + NAD(P)+ \rightleftharpoons L-aspartate 4-semialdehyde + NAD(P)H + H+ The 2 substrates of this enzyme are L-homoserine and NAD+ ...

** Aminopropanol oxidoreductase **

Diacetyl reductase Diacetyl reductase is the name of two acetoin forming enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme conv ...

Glycerol dehydrogenase Glycerol dehydrogenase (, also known as NAD+-linked glycerol dehydrogenase, glycerol: NAD+ 2-oxidoreductase, GDH, GlDH, GlyDH) is an enzyme in the oxidoreductase family that utilizes the NAD+ to catalyze the oxidation of glycerol to form glyceron ...

Propanediol-phosphate dehydrogenase In enzymology, a propanediol-phosphate dehydrogenase () is an enzyme that catalyzes the chemical reaction :propane-1,2-diol 1-phosphate + NAD+ \rightleftharpoons hydroxyacetone phosphate + NADH + H+ Thus, the two substrates of this enzyme are ...

** glycerol-3-phosphate dehydrogenase (NAD+) ** D-xylulose reductase **

L-xylulose reductase Dicarbonyl/L-xylulose reductase, also known as carbonyl reductase II, is an enzyme that in human is encoded by the DCXR gene located on chromosome 17. Structure The DCXR gene encodes a membrane protein that is approximately 34 kDa in size an ...

Lactate dehydrogenase Lactate dehydrogenase (LDH or LD) is an enzyme found in nearly all living cells. LDH catalyzes the conversion of lactate to pyruvate and back, as it converts NAD+ to NADH and back. A dehydrogenase is an enzyme that transfers a hydride from on ...

Malate dehydrogenase Malate dehydrogenase () (MDH) is an enzyme that reversibly catalyzes the oxidation of malate to oxaloacetate using the reduction of NAD+ to NADH. This reaction is part of many metabolic pathways, including the citric acid cycle. Other malate ...

Isocitrate dehydrogenase Isocitrate dehydrogenase (IDH) () and () is an enzyme that catalyzes the oxidative decarboxylation of isocitrate, producing alpha-ketoglutarate (α-ketoglutarate) and CO2. This is a two-step process, which involves oxidation of isocitrate (a s ...

** HMG-CoA reductase * :EC 1.1.2 (with a

cytochrome Cytochromes are redox-active proteins containing a heme, with a central Fe atom at its core, as a cofactor. They are involved in electron transport chain and redox catalysis. They are classified according to the type of heme and its mode of bi ...

as acceptor) * :EC 1.1.3 (with

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

as acceptor) **

Glucose oxidase The glucose oxidase enzyme (GOx or GOD) also known as notatin (EC number 1.1.3.4) is an oxidoreductase that catalyses the oxidation of glucose to hydrogen peroxide and D-glucono-δ-lactone. This enzyme is produced by certain species of fungi and ...

L-gulonolactone oxidase L-Gulonolactone oxidase ( ECbr>1.1.3.8 is an enzyme that produces vitamin C, but is non-functional in Haplorrhini (including humans), in some bats, and in guinea pigs. It catalyzes the reaction of L-gulono-1,4-lactone with oxygen to form L ...

Thiamine oxidase In enzymology, a thiamine oxidase () is an enzyme that catalyzes the chemical reaction ::thiamine + 2 O2 + H2O \rightleftharpoons thiamine acetic acid + 2 H2O2 The 3 substrates of this enzyme are thiamine, O2, and H2O, whereas its two produc ...

Xanthine oxidase Xanthine oxidase (XO, sometimes XAO) is a form of xanthine oxidoreductase, a type of enzyme that generates reactive oxygen species. These enzymes catalyze the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthin ...

* :EC 1.1.4 (with a

disulfide In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...

as acceptor) * :EC 1.1.5 (with a

quinone The quinones are a class of organic compounds that are formally "derived from aromatic compounds uch as benzene or naphthaleneby conversion of an even number of –CH= groups into –C(=O)– groups with any necessary rearrangement of double ...

or similar compound as acceptor) * :EC 1.1.99 (with other acceptors)

:EC 1.2 (act on the aldehyde or oxo group of donors)

* :EC 1.2.1 (with NAD⁺ or NADP⁺ as acceptor) **

Acetaldehyde dehydrogenase Acetaldehyde dehydrogenases () are dehydrogenase enzymes which catalyze the conversion of acetaldehyde into acetic acid. The oxidation of acetaldehyde to acetate can be summarized as follows: Acetaldehyde + NAD+ + Coenzyme A ↔ Acetyl-CoA + NA ...

** Glyceraldehyde 3-phosphate dehydrogenase **

Pyruvate dehydrogenase Pyruvate dehydrogenase is an enzyme that catalyzes the reaction of pyruvate and a lipoamide to give the acetylated dihydrolipoamide and carbon dioxide. The conversion requires the coenzyme thiamine pyrophosphate. Pyruvate dehydrogenase is u ...

* :EC 1.2.4 **

Oxoglutarate dehydrogenase The oxoglutarate dehydrogenase complex (OGDC) or α-ketoglutarate dehydrogenase complex is an enzyme complex, most commonly known for its role in the citric acid cycle. Units Much like pyruvate dehydrogenase complex (PDC), this enzyme forms a co ...

:EC 1.3 (act on the CH-CH group of donors)

* :EC 1.3.1 (with NAD⁺ or NADP⁺ as acceptor) **

Biliverdin reductase Biliverdin reductase (BVR) is an enzyme () found in all tissues under normal conditions, but especially in reticulo-macrophages of the liver and spleen. BVR facilitates the conversion of biliverdin to bilirubin via the reduction of a double-b ...

* :EC 1.3.2 (with a

as acceptor) * :EC 1.3.3 (with

as acceptor) **

Protoporphyrinogen oxidase Protoporphyrinogen oxidase or protox is an enzyme that in humans is encoded by the ''PPOX'' gene. Protoporphyrinogen oxidase is responsible for the seventh step in biosynthesis of protoporphyrin IX. This porphyrin is the precursor to hemoglobin, ...

* :EC 1.3.5 (with a

or similar compound as acceptor) * :EC 1.3.7 (with an

iron–sulfur protein Iron–sulfur proteins (or iron–sulphur proteins in British spelling) are proteins characterized by the presence of iron–sulfur clusters containing sulfide-linked di-, tri-, and tetrairon centers in variable oxidation states. Iron–sulfur cl ...

as acceptor) * :EC 1.3.99 (with other acceptors)

:EC 1.4 (act on the CH-NH₂ group of donors)

* :EC 1.4.3 ** Monoamine oxidase

:EC 1.5 (act on CH-NH group of donors)

* :EC 1.5.1 (with NAD⁺ or NADP⁺ as acceptor) ** Dihydrofolate reductase ** Methylenetetrahydrofolate reductase * :EC 1.5.3 (with

as acceptor) ** Sarcosine oxidase **

Dihydrobenzophenanthridine oxidase Dihydrobenzophenanthridine oxidase (DHBP oxidase) is an enzyme. In the IUBMB Enzyme Nomenclature, dihydrobenzophenanthridine oxidase is . Dihydrobenzophenanthridine oxidase produces oxidized forms of benzophenanthridine alkaloids: * In ''Sanguin ...

* :EC 1.5.4 (with a

as acceptor) * :EC 1.5.5 (with a

or similar compound as acceptor) * :EC 1.5.7 (with an

as acceptor) * :EC 1.5.8 (with a flavin as acceptor) * :EC 1.5.99 (with other acceptors)

:EC 1.6 (act on NADH or NADPH)

* :EC 1.6.1 (with NAD⁺ or NADP⁺ as acceptor) * :EC 1.6.2 (with a

as acceptor) * :EC 1.6.3 (with

as acceptor) *EC 1.6.4 now :EC 1.8.1 * :EC 1.6.5 (with a

or similar compound as acceptor) **

NADH dehydrogenase NADH dehydrogenase is an enzyme that converts nicotinamide adenine dinucleotide (NAD) from its reduced form (NADH) to its oxidized form (NAD+). Members of the NADH dehydrogenase family and analogues are commonly systematically named using the for ...

* :EC 1.6.6 (with a

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

ous group as acceptor) *EC 1.6.7 now :EC 1.18.1 *EC 1.6.8 now :EC 1.5.1 * :EC 1.6.99 (with other acceptors)

:EC 1.7 (act on other nitrogenous compounds as donors)

* :EC 1.7.1 (with NAD⁺ or NADP⁺ as acceptor) * :EC 1.7.2 (with a

as acceptor) * :EC 1.7.3 (with

as acceptor) **

Urate oxidase The enzyme urate oxidase (UO), uricase or factor-independent urate hydroxylase, absent in humans, catalyzes the oxidation of uric acid to 5-hydroxyisourate: :Uric acid + O2 + H2O → 5-hydroxyisourate + H2O2 :5-hydroxyisourate + H2O → allan ...

* :EC 1.7.7 (with an

as acceptor) * :EC 1.7.99 (with other acceptors) ** Nitrite reductase ** Nitrate reductase

:EC 1.8 (act on a sulfur group of donors)

* :EC 1.8.1 (with NAD⁺ or NADP⁺ as acceptor) **

Glutathione reductase Glutathione reductase (GR) also known as glutathione-disulfide reductase (GSR) is an enzyme that in humans is encoded by the GSR gene. Glutathione reductase (EC 1.8.1.7) catalyzes the reduction of glutathione disulfide ( GSSG) to the sulfhydryl f ...

Thioredoxin reductase Thioredoxin reductases (TR, TrxR) () are enzymes that reduce thioredoxin (Trx). Two classes of thioredoxin reductase have been identified: one class in bacteria and some eukaryotes and one in animals. In bacteria TrxR also catalyzes the reduction ...

* :EC 1.8.2 (with a

as acceptor) * :EC 1.8.3 (with

as acceptor) **

Sulfite oxidase Sulfite oxidase () is an enzyme in the mitochondria of all eukaryotes, with exception of the yeasts. It oxidizes sulfite to sulfate and, via cytochrome c, transfers the electrons produced to the electron transport chain, allowing generation o ...

* :EC 1.8.4 (with a

as acceptor) * :EC 1.8.5 (with a

or similar compound as acceptor) *EC 1.8.6 deleted, included in EC 2.5.1.18 * :EC 1.8.7 (with an

as acceptor) * :EC 1.8.98 (with other, known, acceptors) * :EC 1.8.99 (with other acceptors)

:EC 1.9 (act on a
heme Heme, or haem (pronounced / hi:m/ ), is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver. In biochemical terms, heme is a coordination complex "consis ...
group of donors)

* :EC 1.9.3 (with

as acceptor) **

Cytochrome c oxidase The enzyme cytochrome c oxidase or Complex IV, (was , now reclassified as a translocasEC 7.1.1.9 is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes. It is the last enzyme in the respiratory elect ...

* :EC 1.9.6 (with a

ous as acceptor) *EC 1.9.99 transferred, now EC 1.9.98.1

:EC 1.10 (act on diphenols and related substances as donors)

* :EC 1.10.1(with NAD⁺ or NADP⁺ as acceptor) * :EC 1.10.2 (with a

as acceptor) **

Coenzyme Q - cytochrome c reductase A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's role as a catalyst (a catalyst is a substance that increases the rate of a chemical reaction). Cofactors can be considered "helper molecules" that ass ...

* :EC 1.10.3 (with

as acceptor) **

Catechol oxidase Catechol oxidase is a copper oxidase that contains a type 3 di-copper cofactor and catalyzes the oxidation of ortho-diphenols into ortho-quinones coupled with the reducing agent, reduction of molecular oxygen to water. It is present in a variet ...

Laccase Laccases () are multicopper oxidases found in plants, fungi, and bacteria. Laccases oxidize a variety of phenolic substrates, performing one-electron oxidations, leading to crosslinking. For example, laccases play a role in the formation of l ...

* :EC 1.10.99 (with other acceptors)

:EC 1.11 (act on
peroxide In chemistry, peroxides are a group of compounds with the structure , where R = any element. The group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable. The most common peroxide is hydrogen p ...
as an acceptor --
peroxidase Peroxidases or peroxide reductases ( EC numberbr>1.11.1.x are a large group of enzymes which play a role in various biological processes. They are named after the fact that they commonly break up peroxides. Functionality Peroxidases typically ca ...
s)

* :EC 1.11.1 (

peroxidase Peroxidases or peroxide reductases ( EC numberbr>1.11.1.x are a large group of enzymes which play a role in various biological processes. They are named after the fact that they commonly break up peroxides. Functionality Peroxidases typically ca ...

s) **

Cytochrome c peroxidase Cytochrome ''c'' peroxidase, or CCP, is a water-soluble heme-containing enzyme of the peroxidase family that takes reducing equivalents from cytochrome ''c'' and reduces hydrogen peroxide to water: :CCP + H2O2 + 2 ferrocytochrome ''c'' + 2H+ → ...

** Catalase **

Myeloperoxidase Myeloperoxidase (MPO) is a peroxidase enzyme that in humans is encoded by the ''MPO'' gene on chromosome 17. MPO is most abundantly expressed in neutrophil granulocytes (a subtype of white blood cells), and produces hypohalous acids to carry ou ...

Thyroid peroxidase Thyroid peroxidase, also called thyroperoxidase (TPO) or iodide peroxidase, is an enzyme expressed mainly in the thyroid where it is secreted into colloid. Thyroid peroxidase oxidizes iodide ions to form iodine atoms for addition onto tyrosine re ...

Glutathione peroxidase Glutathione peroxidase (GPx) () is the general name of an enzyme family with peroxidase activity whose main biological role is to protect the organism from oxidative damage. The biochemical function of glutathione peroxidase is to reduce lipid h ...

:EC 1.12 (act on hydrogen as a donor)

* :EC 1.12.1 (with NAD⁺ or NADP⁺ as acceptor) * :EC 1.12.2 (with a

as acceptor) * :EC 1.12.5 (with a

or similar compound as acceptor) * :EC 1.12.7 (with an

as acceptor) * :EC 1.12.98 (with other known acceptors) * :EC 1.12.99 (with other acceptors)

:EC 1.13 (act on single donors with incorporation of molecular oxygen)

* :EC 1.13.11 (With incorporation of two atoms of oxygen) ** 4-hydroxyphenylpyruvate dioxygenase () * :EC 1.13.12 (With incorporation of one atom of oxygen (internal monooxygenases or internal mixed function oxidases)) ** Renilla-luciferin 2-monooxygenase ** Cypridina-luciferin 2-monooxygenase **

Firefly luciferase Firefly luciferase is the luciferase, light-emitting enzyme responsible for the bioluminescence of fireflies and click beetles. The enzyme catalyses the oxidation of firefly luciferin, requiring oxygen and Adenosine triphosphate, ATP. Because of ...

** Watasenia-luciferin 2-monooxygenase ** Oplophorus-luciferin 2-monooxygenase

:EC 1.14 (act on paired donors with incorporation of molecular oxygen)

Cytochrome P450 oxidase Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various compo ...

* :Cytochrome P450 **

Aromatase Aromatase (), also called estrogen synthetase or estrogen synthase, is an enzyme responsible for a key step in the biosynthesis of estrogens. It is CYP19A1, a member of the cytochrome P450 superfamily, which are monooxygenases that catalyze many ...

CYP2D6 Cytochrome P450 2D6 (CYP2D6) is an enzyme that in humans is encoded by the ''CYP2D6'' gene. ''CYP2D6'' is primarily expressed in the liver. It is also highly expressed in areas of the central nervous system, including the substantia nigra. CYP2D ...

CYP2E1 Cytochrome P450 2E1 (abbreviated CYP2E1, ) is a member of the cytochrome P450 mixed-function oxidase system, which is involved in the metabolism of xenobiotics in the body. This class of enzymes is divided up into a number of subcategories, includ ...

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from t ...

* :EC 1.14.12 ** Nitric oxide dioxygenase * :EC 1.14.13 **

Nitric oxide synthase Nitric oxide synthases () (NOSs) are a family of enzymes catalyzing the production of nitric oxide (NO) from L-arginine. NO is an important cellular signaling molecule. It helps modulate vascular tone, insulin secretion, airway tone, and p ...

* :EC 1.14.14 **

* :EC 1.14.16 **

Phenylalanine hydroxylase Phenylalanine hydroxylase. (PAH) () is an enzyme that catalyzes the hydroxylation of the aromatic side-chain of phenylalanine to generate tyrosine. PAH is one of three members of the biopterin-dependent aromatic amino acid hydroxylases, a class ...

* :EC 1.14.18 **

Tyrosinase Tyrosinase is an oxidase that is the rate-limiting enzyme for controlling the production of melanin. The enzyme is mainly involved in two distinct reactions of melanin synthesis otherwise known as the Raper Mason pathway. Firstly, the hydroxy ...

:EC 1.15 (act on superoxide radicals as acceptors)

* :EC 1.15.1 ** Superoxide dismutase

:EC 1.16 (oxidize metal ions)

* :EC 1.16.3 **

Ceruloplasmin Ceruloplasmin (or caeruloplasmin) is a ferroxidase enzyme that in humans is encoded by the ''CP'' gene. Ceruloplasmin is the major copper-carrying protein in the blood, and in addition plays a role in iron metabolism. It was first described in 1 ...

:EC 1.17 (act on CH or CH₂ groups)

* :EC 1.17.1 ** Leucoanthocyanidin reductase **

Xanthine dehydrogenase Xanthine dehydrogenase, also known as XDH, is a protein that, in humans, is encoded by the ''XDH'' gene. Function Xanthine dehydrogenase belongs to the group of molybdenum-containing hydroxylases involved in the oxidative metabolism of purin ...

** Nicotinate dehydrogenase ** 4-hydroxy-tetrahydrodipicolinate reductase * :EC 1.17.2 **

Nicotinate dehydrogenase (cytochrome) Nicotinate dehydrogenase (cytochrome) (, ''nicotinic acid hydroxylase'', ''nicotinate hydroxylase'') is an enzyme with List of enzymes, systematic name ''nicotinate:cytochrome 6-oxidoreductase (hydroxylating)''. This enzyme catalysis, catalyses the ...

* :EC 1.17.3 **

* :EC 1.17.4 ** Ribonucleotide reductase ** Ribonucleoside-triphosphate reductase **

Vitamin K epoxide reductase Vitamin K epoxide reductase (VKOR) is an enzyme () that reduces vitamin K after it has been oxidised in the carboxylation of glutamic acid residues in blood coagulation enzymes. VKOR is a member of a large family of predicted enzymes that are pre ...

** Vitamin-K-epoxide reductase (warfarin-sensitive) ** Vitamin-K-epoxide reductase (warfarin-insensitive) **

RRM1 Ribonucleoside-diphosphate reductase large subunit is an enzyme that in humans is encoded by the ''RRM1'' gene. This gene encodes one of two non-identical subunits which constitute ribonucleoside-diphosphate reductase, an enzyme essential for the ...

RRM2 Ribonucleoside-diphosphate reductase subunit M2, also known as ribonucleotide reductase small subunit, is an enzyme that in humans is encoded by the ''RRM2'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gen ...

** RRM2B * :EC 1.17.5 ** Caffeine dehydrogenase * :EC 1.17.7 * :EC 1.17.99

:EC 1.18 (act on iron–sulfur proteins as donors)

* :EC 1.18.6 **

Nitrogenase Nitrogenases are enzymes () that are produced by certain bacteria, such as cyanobacteria (blue-green bacteria) and rhizobacteria. These enzymes are responsible for the Organic redox reaction, reduction of nitrogen (N2) to ammonia (NH3). Nitrog ...

:EC 1.19 (act on reduced flavodoxin as donor)

* :EC 1.19.6 ** Nitrogenase (flavodoxin)

:EC 1.20 (act on phosphorus or arsenic as donors)

* :EC 1.20.1 * :EC 1.20.2 * :EC 1.20.4 **

Arsenate reductase (glutaredoxin) Arsenate reductase (glutaredoxin) () is an enzyme that catalysis, catalyzes the chemical reaction :arsenate + glutaredoxin \rightleftharpoons arsenite + glutaredoxin disulfide + H2O Thus, the two substrate (biochemistry), substrates of this enzy ...

Glutaredoxin Glutaredoxins (also known as Thioltransferase) are small redox enzymes of approximately one hundred amino-acid residues that use glutathione as a cofactor. In humans this oxidation repair enzyme is also known to participate in many cellular functi ...

* :EC 1.20.9 * :EC 1.20.99

:EC 1.21 (act on X-H and Y-H to form an X-Y bond)

* :EC 1.21.1 **

Iodotyrosine deiodinase Iodotyrosine deiodinase, also known as iodotyrosine dehalogenase 1, is a type of deiodinase enzyme that scavenges iodide by removing it from iodinated tyrosine residues in the thyroid gland. These iodinated tyrosines are produced during thyroid h ...

* :EC 1.21.3 **

Isopenicillin N synthase Isopenicillin N synthase (IPNS) is a non-heme iron protein belongig to the 2-oxoglutarate (2OG)-dependent dioxygenases oxidoreductase family. This enzyme catalyzes the formation of isopenicillin N from δ-(L-α-aminoadipoyl)-L-cysteinyl-D-valin ...

Tetrahydrocannabinolic acid synthase Tetrahydrocannabinolic acid (THCA) synthase (full name ''Δ1-tetrahydrocannabinolic acid synthase'') is an enzyme responsible for catalyzing the formation of THCA from cannabigerolic acid (CBGA). THCA is the direct precursor of tetrahydrocann ...

* :EC 1.21.4 * :EC 1.21.99 **

Thyroxine 5-deiodinase Thyroxine 5-deiodinase also known as type III iodothyronine deiodinase (EC number 1.21.99.3) is an enzyme that in humans is encoded by the ''DIO3'' gene. This enzyme catalyses the following chemical reaction : 3,3',5'-triiodo-L-thyronine + iod ...

Iodothyronine deiodinase Iodothyronine deiodinases ( and ) are a subfamily of deiodinase enzymes important in the activation and deactivation of thyroid hormones. Thyroxine (T4), the precursor of 3,5,3'-triiodothyronine (T3) is transformed into T3 by deiodinase activity ...

and

:EC 1.97 (other oxidoreductases)

* :EC 1.97.1 **

Deiodinase Deiodinase (or "Monodeiodinase") is a peroxidase enzyme that is involved in the activation or deactivation of thyroid hormones. Types Types of deiodinases include: Iodothyronine deiodinases catalyze release of iodine directly from the thyro ...

:Transferases (EC 2) (
Transferase A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of ...
)

Glutathione S-transferase Glutathione ''S''-transferases (GSTs), previously known as ligandins, are a family of eukaryotic and prokaryotic phase II metabolic isozymes best known for their ability to catalyze the conjugation of the reduced form of glutathione (GSH) ...

:EC 2.1 (transfer one-carbon groups,
Methylase Methyltransferases are a large group of enzymes that all methylate their substrates but can be split into several subclasses based on their structural features. The most common class of methyltransferases is class I, all of which contain a Rossm ...
)

* :EC 2.1.1 **

Catechol-O-methyl transferase Catechol-''O''-methyltransferase (COMT; ) is one of several enzymes that degrade catecholamines (neurotransmitters such as dopamine, epinephrine, and norepinephrine), catecholestrogens, and various drugs and substances having a catechol struct ...

DNA methyltransferase In biochemistry, the DNA methyltransferase (DNA MTase, DNMT) family of enzymes catalyze the transfer of a methyl group to DNA. DNA methylation serves a wide variety of biological functions. All the known DNA methyltransferases use S-adenosyl m ...

, , ** Histone methyltransferase , * :EC 2.1.3 **

Aspartate transcarbamoylase Aspartate carbamoyltransferase (also known as aspartate transcarbamoylase or ATCase) catalyzes the first step in the pyrimidine biosynthetic pathway (). In '' E. coli'', the enzyme is a multi- subunit protein complex composed of 12 subunits (3 ...

Ornithine transcarbamoylase Ornithine transcarbamylase (OTC) (also called ornithine carbamoyltransferase) is an enzyme () that catalyzes the reaction between carbamoyl phosphate (CP) and ornithine (Orn) to form citrulline (Cit) and phosphate (Pi). There are two classes of OT ...

:EC 2.2 (transfer
aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...
or
ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bo ...
groups)

* :EC 2.2.1 **

Transketolase Transketolase (abbreviated as TK) is an enzyme that is encoded by the TKT gene. It participates in both the pentose phosphate pathway in all organisms and the Calvin cycle of photosynthesis. Transketolase catalyzes two important reactions, whic ...

Transaldolase Transaldolase is an enzyme () of the non-oxidative phase of the pentose phosphate pathway. In humans, transaldolase is encoded by the ''TALDO1'' gene. The following chemical reaction is catalyzed by transaldolase: : sedoheptulose 7-phosph ...

Acetolactate synthase The acetolactate synthase (ALS) enzyme (also known as acetohydroxy acid or acetohydroxyacid synthase, abbr. AHAS) is a protein found in plants and micro-organisms. ALS catalyzes the first step in the synthesis of the branched-chain amino acids ( ...

** 2-Succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic-acid synthase

:EC 2.3 (acyltransferases)

* :EC 2.3.1 **

Aminolevulinic acid synthase Aminolevulinic acid synthase (ALA synthase, ALAS, or delta-aminolevulinic acid synthase) is an enzyme () that catalyzes the synthesis of δ-aminolevulinic acid (ALA) the first common precursor in the biosynthesis of all tetrapyrroles such as hem ...

** Choline acetyltransferase * :EC 2.3.2 **

Factor XIII Factor XIII or fibrin stabilizing factor is a zymogen found in blood of humans and some other animals. It is activated by thrombin to factor XIIIa. Factor XIIIa is an enzyme of the blood coagulation system that crosslinks fibrin. Deficiency of X ...

Gamma glutamyl transpeptidase Gamma-glutamyltransferase (also γ-glutamyltransferase, GGT, gamma-GT, gamma-glutamyl transpeptidase; ) is a transferase (a type of enzyme) that catalyzes the transfer of gamma-glutamyl functional groups from molecules such as glutathione to ...

Transglutaminase Transglutaminases are enzymes that in nature primarily catalyze the formation of an isopeptide bond between γ-carboxamide groups ( -(C=O)NH2 ) of glutamine residue side chains and the ε-amino groups ( -NH2 ) of lysine residue side cha ...

:EC 2.4 (glycosyltransferases)

* :EC 2.4.2 **

Hypoxanthine-guanine phosphoribosyltransferase Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is an enzyme encoded in humans by the ''HPRT1'' gene. HGPRT is a transferase that catalyzes conversion of hypoxanthine to inosine monophosphate and guanine to guanosine monophosphate. This r ...

:EC 2.5 * :EC 2.5.1 **

Thiaminase Thiaminase is an enzyme that metabolizes or breaks down thiamine into two molecular parts. It is an antinutrient when consumed. The old name was "aneurinase". There are two types: * Thiamine pyridinylase, Thiaminase I (, ) * Aminopyrimidine am ...

:EC 2.5 (transfer
alkyl In organic chemistry, an alkyl group is an alkane missing one hydrogen. The term ''alkyl'' is intentionally unspecific to include many possible substitutions. An acyclic alkyl has the general formula of . A cycloalkyl is derived from a cycloalk ...
or
aryl In organic chemistry, an aryl is any functional group or substituent derived from an aromatic ring, usually an aromatic hydrocarbon, such as phenyl and naphthyl. "Aryl" is used for the sake of abbreviation or generalization, and "Ar" is used as ...
groups, other than
methyl In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many ...
groups)

** Flavin prenyltransferase

:EC 2.6 (transfer nitrogenous groups)

* :EC 2.6.1 **

Alanine transaminase Alanine transaminase (ALT) is a transaminase enzyme (). It is also called alanine aminotransferase (ALT or ALAT) and was formerly called serum glutamate-pyruvate transaminase or serum glutamic-pyruvic transaminase (SGPT) and was first characte ...

Aspartate transaminase Aspartate transaminase (AST) or aspartate aminotransferase, also known as AspAT/ASAT/AAT or (serum) glutamic oxaloacetic transaminase (GOT, SGOT), is a pyridoxal phosphate (PLP)-dependent transaminase enzyme () that was first described by Arthur ...

:EC 2.7 (transfer phosphorus-containing groups)

* :EC 2.7.2 ** Butyrate kinase ()

:EC 2.8 (transfer sulfur-containing groups)

* : Thiosulfate sulfurtransferase * : 3-mercaptopyruvate sulfurtransferase * : Thiosulfate—thiol sulfurtransferase * : tRNA uracil 4-sulfurtransferase * : Thiosulfate—dithiol sulfurtransferase * : Biotin synthase * :

Cysteine desulfurase Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, somet ...

* :

Lipoyl synthase Lipoyl synthase is an enzyme that belongs to the radical SAM ( ''S''-adenosyl methionine) family. Within the radical SAM superfamily, lipoyl synthase is in a sub-family of enzymes that catalyze sulfur insertion reactions. Enzymes in this family co ...

* :

Molybdenum cofactor sulfurtransferase Molybdenum cofactor sulfurtransferase (, ''molybdenum cofactor sulfurase'', ''ABA3'', ''MoCo sulfurase'', ''MoCo sulfurtransferase'') is an enzyme with systematic name ''L-cysteine:molybdenum cofactor sulfurtransferase''. This enzyme catalyses t ...

* : Thiazole synthase * : Molybdopterin synthase sulfurtransferase * :

Molybdopterin synthase Molybdopterin synthase (, MPT synthase) is an enzyme required to synthesize molybdopterin (MPT) from precursor Z (now known as cyclic pyranopterin monophosphate). Molydopterin is subsequently complexed with molybdenum to form molybdenum cofactor ( ...

* : tRNA-uridine 2-sulfurtransferase * : tRNA-5-taurinomethyluridine 2-sulfurtransferase * : tRNA-5-methyluridine(54) 2-sulfurtransferase

:EC 2.9 (transfer selenium-containing groups)

* : L-seryl-tRNA(Sec) selenium transferase * : O-phospho-L-seryl-tRNA(Sec):L-selenocysteinyl-tRNA synthase

:Hydrolases (EC 3) (
Hydrolase Hydrolase is a class of enzyme that commonly perform as biochemical catalysts that use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules. Some common examples of hydrolase enzymes are este ...
)

Hydrolytic enzyme Hydrolase is a class of enzyme that commonly perform as biochemical catalysts that use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules. Some common examples of hydrolase enzymes are es ...

:EC 3.1 (act on
ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
bonds)

* Nuclease *

Endonuclease Endonucleases are enzymes that cleave the phosphodiester bond within a polynucleotide chain. Some, such as deoxyribonuclease I, cut DNA relatively nonspecifically (without regard to sequence), while many, typically called restriction endonucleases ...

* Exonuclease * :EC 3.1.1 **

Acid hydrolase An acid hydrolase is an enzyme that works best at acidic pHs. It is commonly located in lysosomes, which are acidic on the inside. Acid hydrolases may be nucleases, proteases, glycosidases, lipases, phosphatases, sulfatases and phospholipases ...

Phospholipase A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. Acids trigger the release of bound calcium from cellular stores and the consequent increase in free cytosolic Ca2+, an essential step in ...

A () **

Acetylcholinesterase Acetylcholinesterase (HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme Enzymes () are proteins that a ...

() **

Cholinesterase The enzyme cholinesterase (EC 3.1.1.8, choline esterase; systematic name acylcholine acylhydrolase) catalyses the hydrolysis of choline-based esters: : an acylcholine + H2O = choline + a carboxylate Several of these serve as neurotransmitters ...

() **

Lipoprotein lipase Lipoprotein lipase (LPL) (EC 3.1.1.34, systematic name triacylglycerol acylhydrolase (lipoprotein-dependent)) is a member of the lipase gene family, which includes pancreatic lipase, hepatic lipase, and endothelial lipase. It is a water-soluble ...

() * :EC 3.1.2 **

Ubiquitin carboxy-terminal hydrolase L1 Ubiquitin carboxy-terminal hydrolase L1 (, ''ubiquitin C-terminal hydrolase'', ''UCH-L1'') is a deubiquitinating enzyme. Function UCH-L1 is a member of a gene family whose products hydrolyze small C-terminal adducts of ubiquitin to generate ...

() * :EC 3.1.3 ** Phosphatase ** Alkaline phosphatase () ** Fructose bisphosphatase () * :EC 3.1.4 **

C () **

CGMP specific phosphodiesterase type 5 Cyclic guanosine monophosphate-specific phosphodiesterase type 5 is an enzyme () from the phosphodiesterase class. It is found in various tissues, most prominently the corpus cavernosum and the retina. It has also been recently discovered to p ...

() **

D () * :EC 3.1.21 **

Restriction enzyme A restriction enzyme, restriction endonuclease, REase, ENase or'' restrictase '' is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. Restriction enzymes are one class o ...

Type 1 () **

Type 2 () **

Type 3 () **

Type 4 (?) **

Deoxyribonuclease Deoxyribonuclease (DNase, for short) refers to a group of glycoprotein endonucleases which are enzymes that catalyze the hydrolytic cleavage of phosphodiester linkages in the DNA backbone, thus degrading DNA. The role of the DNase enzyme in cells ...

I () * :EC 3.1.26 **

RNase H Ribonuclease H (abbreviated RNase H or RNH) is a family of non-sequence-specific endonuclease enzymes that catalyze the cleavage of RNA in an RNA/ DNA substrate via a hydrolytic mechanism. Members of the RNase H family can be found in nearly ...

() * :EC 3.1.27 **

Ribonuclease Ribonuclease (commonly abbreviated RNase) is a type of nuclease that catalyzes the degradation of RNA into smaller components. Ribonucleases can be divided into endoribonucleases and exoribonucleases, and comprise several sub-classes within ...

:EC 3.2 (act on sugars - glycosylases)

* :EC 3.2.1 **

Amylase An amylase () is an enzyme that catalyses the hydrolysis of starch (Latin ') into sugars. Amylase is present in the saliva of humans and some other mammals, where it begins the chemical process of digestion. Foods that contain large amounts of ...

() ** Sucrase () **

Chitinase Chitinases (EC 3.2.1.14, chitodextrinase, 1,4-β-poly-N-acetylglucosaminidase, poly-β-glucosaminidase, β-1,4-poly-N-acetyl glucosamidinase, poly ,4-(N-acetyl-β-D-glucosaminide)glycanohydrolase, (1→4)-2-acetamido-2-deoxy-β-D-glucan glycano ...

() **

Lysozyme Lysozyme (EC 3.2.1.17, muramidase, ''N''-acetylmuramide glycanhydrolase; systematic name peptidoglycan ''N''-acetylmuramoylhydrolase) is an antimicrobial enzyme produced by animals that forms part of the innate immune system. It is a glycoside ...

() **

Maltase Maltase (, ''alpha-glucosidase'', ''glucoinvertase'', ''glucosidosucrase'', ''maltase-glucoamylase'', ''alpha-glucopyranosidase'', ''glucosidoinvertase'', ''alpha-D-glucosidase'', ''alpha-glucoside hydrolase'', ''alpha-1,4-glucosidase'', ''alp ...

() **

Lactase Lactase is an enzyme produced by many organisms. It is located in the brush border of the small intestine of humans and other mammals. Lactase is essential to the complete digestion of whole milk; it breaks down lactose, a sugar which gives ...

() **

Beta-galactosidase β-Galactosidase (EC 3.2.1.23, lactase, beta-gal or β-gal; systematic name β-D-galactoside galactohydrolase), is a glycoside hydrolase enzyme that catalyzes hydrolysis of terminal non-reducing β-D-galactose residues in β-D-galactosides. β- ...

() **

Hyaluronidase Hyaluronidases are a family of enzymes that catalyse the degradation of hyaluronic acid (HA). Karl Meyer classified these enzymes in 1971, into three distinct groups, a scheme based on the enzyme reaction products. The three main types of hyal ...

()

Function and clinical importance of some enzymes in category 3.2.1

Amylase

''Function'': Amylase is an enzyme that is responsible for the breaking of the bonds in starches, polysaccharides, and complex carbohydrates to be turned into simple sugars that will be easier to absorb. ''Clinical Significance'': Amylase also has medical history in the use of Pancreatic Enzyme Replacement Therapy (PERT). One of the components is Sollpura (liprotamase), which help in the breakdown of saccharides into simple sugars.

Lysozyme

''Function'': An enzyme that is produced by animals that forms part of the innate immune system and is abundant in the secretions of saliva, human milk, tears, and mucus. It functions as an antimicrobial agent by splitting the peptidoglycan component of bacterial cell walls, which then leads to cell death. ''Clinical Significance'': Toxic levels of blood are caused by the excessive production of lysozyme's by cancer cells. Lysozyme's have also been associated with Bronchopulmonary dysplasia (BPD) in newborns and is a key factor in providing the immunology of infants during breast feeding.

Sucrase

''Function'': Sucrase is a stomachs related protein that mobilizes hydrolysis to convert sucrose into glucose and fructose. ''Clinical Significance'': Low amounts of Sucrose also known as Sucrose intolerance happens when sucrose isn’t being discharged in the small digestive tract. A result of this is extra gas.

Lactase

''Function'': lactase is located in the small digestives system of people and other creatures such as

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

. Lactase is the bases of the total absorption of milk. ''Clinical Significance'': People who are lactose intolerant have medicine that can help with the digestion. When you are lactose intolerant you might experience gas, bloating, and pain along with other symptoms regarding your digestive system.

:EC 3.3 (act on
ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...
bonds)

* :EC 3.3 * Adenosylmethionine hydrolase *

S-adenosyl-L-homocysteine hydrolase S-adenosyl-L-homocysteine hydrolase () (AdoHcyase) is an enzyme of the activated methyl cycle, responsible for the reversible hydration of S-adenosyl-L-homocysteine into adenosine and homocysteine. AdoHcyase is a ubiquitous enzyme which binds a ...

* Alkenylglycerophosphocholine hydrolase * Alkenylglycerophosphoethanolamine hydrolase * Cholesterol-5,6-oxide hydrolase * Hepoxilin-epoxide hydrolase * Isochorismatase *

Leukotriene-A4 hydrolase Leukotriene A4 hydrolase, also known as LTA4H is a human gene. The protein encoded by this gene is a bifunctional enzyme () which converts leukotriene A4 to leukotriene B4 and acts as an aminopeptidase. Function This enzyme belongs to the family ...

* Limonene-1,2-epoxide hydrolase *

Microsomal epoxide hydrolase In enzymology, a microsomal epoxide hydrolase (mEH) () is an enzyme that catalyzes the hydrolysis reaction between an epoxide and water to form a diol. This enzyme plays a role in the uptake of bile salts within the large intestine. It functio ...

* Trans-epoxysuccinate hydrolase

:EC 3.4 (act on
peptide bond In organic chemistry, a peptide bond is an amide type of covalent chemical bond linking two consecutive alpha-amino acids from C1 (carbon number one) of one alpha-amino acid and N2 (nitrogen number two) of another, along a peptide or protein cha ...
s -
Peptidase A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the for ...
)

* :EC 3.4.11 ** Alanine aminopeptidase * :EC 3.4.15 **

Angiotensin converting enzyme Angiotensin-converting enzyme (), or ACE, is a central component of the renin–angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasoconstr ...

* :EC 3.4.21 **

Serine protease Serine proteases (or serine endopeptidases) are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. ...

** Chymotrypsin () **

Trypsin Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting these long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the dig ...

() **

Thrombin Thrombin (, ''fibrinogenase'', ''thrombase'', ''thrombofort'', ''topical'', ''thrombin-C'', ''tropostasin'', ''activated blood-coagulation factor II'', ''blood-coagulation factor IIa'', ''factor IIa'', ''E thrombin'', ''beta-thrombin'', ''gamma- ...

() **

Factor X Factor X, also known by the eponym Stuart–Prower factor, is an enzyme () of the coagulation cascade. It is a serine endopeptidase (protease group S1, PA clan). Factor X is synthesized in the liver and requires vitamin K for its synthesis. Fa ...

() **

Plasmin Plasmin is an important enzyme () present in blood that degrades many blood plasma proteins, including fibrin clots. The degradation of fibrin is termed fibrinolysis. In humans, the plasmin protein (in the zymogen form of plasminogen) is encode ...

() **

Acrosin Acrosin is a digestive enzyme that acts as a protease. In humans, acrosin is encoded by the ''ACR'' gene. Acrosin is released from the acrosome of spermatozoa as a consequence of the acrosome reaction. It aids in the penetration of the Zona Pellu ...

() **

Factor VII Coagulation factor VII (, formerly known as proconvertin) is one of the proteins that causes blood to clot in the coagulation cascade, and in humans is coded for by the gene ''F7''. It is an enzyme of the serine protease class. Once bound to ti ...

() **

Factor IX Factor IX (or Christmas factor) () is one of the serine proteases of the coagulation system; it belongs to peptidase family S1. Deficiency of this protein causes haemophilia B. It was discovered in 1952 after a young boy named Stephen Christmas ...

() **

Prolyl oligopeptidase Prolyl endopeptidase (PE) also known as prolyl oligopeptidase or post-proline cleaving enzyme is an enzyme that in humans is encoded by the ''PREP'' gene. Function Prolyl endopeptidase is a large cytosolic enzyme that belongs to a distinct cla ...

() **

Factor XI Factor XI or plasma thromboplastin antecedent is the zymogen form of factor XIa, one of the enzymes of the coagulation cascade. Like many other coagulation factors, it is a serine protease. In humans, Factor XI is encoded by the ''F11'' gene. ...

() **

Elastase In molecular biology, elastase is an enzyme from the class of ''proteases (peptidases)'' that break down proteins. In particular, it is a serine protease. Forms and classification Eight human genes exist for elastase: Some bacteria (includin ...

() **

Factor XII Coagulation factor XII, also known as Hageman factor, is a plasma protein. It is the zymogen form of factor XIIa, an enzyme () of the serine protease (or serine endopeptidase) class. In humans, factor XII is encoded by the ''F12'' gene. Struc ...

() **

Proteinase K In molecular biology Proteinase K (, ''protease K'', ''endopeptidase K'', ''Tritirachium alkaline proteinase'', ''Tritirachium album serine proteinase'', ''Tritirachium album proteinase K'') is a broad-spectrum serine protease. The enzyme was dis ...

() **

Tissue plasminogen activator Tissue plasminogen activator (abbreviated tPA or PLAT) is a protein involved in the breakdown of blood clots. It is a serine protease () found on endothelial cells, the cells that line the blood vessels. As an enzyme, it catalyzes the conversion ...

() **

Protein C Protein C, also known as autoprothrombin IIA and blood coagulation factor XIX, is a zymogen, that is, an inactive enzyme. The activated form plays an important role in regulating anticoagulation, inflammation, and cell death and maintainin ...

() * :EC 3.4.22 **

Separase Separase, also known as separin, is a cysteine protease responsible for triggering anaphase by hydrolysing cohesin, which is the protein responsible for binding sister chromatids during the early stage of anaphase. In humans, separin is encoded ...

() * :EC 3.4.23 **

Pepsin Pepsin is an endopeptidase that breaks down proteins into smaller peptides. It is produced in the gastric chief cells of the stomach lining and is one of the main digestive enzymes in the digestive systems of humans and many other animals, w ...

() ** Rennet () **

Renin Renin (etymology and pronunciation), also known as an angiotensinogenase, is an aspartic protease protein and enzyme secreted by the kidneys that participates in the body's renin–angiotensin–aldosterone system (RAAS)—also known as the r ...

() **

Trypsinogen Trypsinogen () is the precursor form (or zymogen) of trypsin, a digestive enzyme. It is produced by the pancreas and found in pancreatic juice, along with amylase, lipase, and chymotrypsinogen. It is cleaved to its active form, trypsin, by ent ...

() and (20/21/23/24/26) **

Plasmepsin Plasmepsins are a class of at least 10 enzymes ( and ) produced by the ''Plasmodium falciparum'' parasite. There are ten different isoforms of these proteins and ten genes coding them respectively in ''Plasmodium'' (Plm I, II, III, IV, V, VI, VII ...

() * :EC 3.4.24 **

Matrix metalloproteinase Matrix metalloproteinases (MMPs), also known as matrix metallopeptidases or matrixins, are metalloproteinases that are calcium-dependent zinc-containing endopeptidases; other family members are adamalysins, serralysins, and astacins. The MMPs be ...

() * :EC 3.4.25 **

Metalloendopeptidase A metalloendopeptidase is an enzyme that functions as a metalloproteinase endopeptidase Endopeptidase or endoproteinase are proteolytic peptidases that break peptide bonds of nonterminal amino acids (i.e. within the molecule), in contrast to exop ...

:EC 3.5 (act on carbon–nitrogen bonds, other than peptide bonds)

* :EC 3.5.1 (In linear amides) **

Urease Ureases (), functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. Ureases are found in numerous bacteria, fungi, algae, plants, and some invertebrates, as well as in soils, as a soil enzyme. They are nickel-contai ...

() * :EC 3.5.2 (In cyclic amides) **

Beta-lactamase Beta-lactamases, (β-lactamases) are enzymes () produced by bacteria that provide multi-resistance to beta-lactam antibiotics such as penicillins, cephalosporins, cephamycins, monobactams and carbapenems ( ertapenem), although carbap ...

() * :EC 3.5.3 (In linear amidines) **

Arginase Arginase (, ''arginine amidinase'', ''canavanase'', ''L-arginase'', ''arginine transamidinase'') is a manganese-containing enzyme. The reaction catalyzed by this enzyme is: : arginine + H2O → ornithine + urea It is the final enzyme of the ure ...

() * :EC 3.5.4 (In cyclic amidines) **

Adenosine deaminase Adenosine deaminase (also known as adenosine aminohydrolase, or ADA) is an enzyme () involved in purine metabolism. It is needed for the breakdown of adenosine from food and for the turnover of nucleic acids in tissues. Its primary function ...

() **

GTP cyclohydrolase I GTP cyclohydrolase I (GTPCH) () is a member of the GTP cyclohydrolase family of enzymes. GTPCH is part of the folate and biopterin biosynthesis pathways. It is responsible for the hydrolysis of guanosine triphosphate (GTP) to form 7,8-dihydrone ...

() * :EC 3.5.5 (In nitriles) **

Nitrilase Nitrilase enzymes (nitrile aminohydrolase; ) catalyse the hydrolysis of nitriles to carboxylic acids and ammonia, without the formation of "free" amide intermediates. Nitrilases are involved in natural product biosynthesis and post translational mo ...

()

:EC 3.6 (act on
acid anhydride An acid anhydride is a type of chemical compound derived by the removal of water molecules from an acid. In organic chemistry, organic acid anhydrides contain the functional group R(CO)O(CO)R'. Organic acid anhydrides often form when one equivale ...
s)

* :EC 3.6.1 **

Helicase Helicases are a class of enzymes thought to be vital to all organisms. Their main function is to unpack an organism's genetic material. Helicases are motor proteins that move directionally along a nucleic acid phosphodiester backbone, separatin ...

DnaB helicase DnaB helicase is an enzyme in bacteria which opens the replication fork during DNA replication. Although the mechanism by which DnaB both couples ATP hydrolysis to translocation along DNA and denatures the duplex is unknown, a change in the qua ...

RecQ helicase RecQ helicase is a family of helicase enzymes initially found in ''Escherichia coli'' that has been shown to be important in genome maintenance. They function through catalyzing the reaction ATP + H2O → ADP + P and thus driving the unwind ...

* :EC 3.6.3 ** ATPase ** NaKATPase () ** ATP synthase ()

:EC 3.7 (act on carbon–carbon bonds)

Kynureninase Kynureninase or L-Kynurenine hydrolase (KYNU) () is a PLP dependent enzyme that catalyses the cleavage of kynurenine (Kyn) into anthranilic acid (Ant). It can also act on 3-hydroxykynurenine (to produce 3-hydroxyanthranilate) and some other (3 ...

:EC 3.8 (act on halide bonds)

* EC 3.8.1.3

Haloacetate dehalogenase In enzymology, a haloacetate dehalogenase () is an enzyme that catalyzes the chemical reaction :haloacetate + H2O \rightleftharpoons glycolate + halide Thus, the two substrates of this enzyme are haloacetate and H2O, whereas its two product ...

:EC 3.9 (act on phosphorus–nitrogen bonds)

* : Phosphoamidase * : Protein arginine phosphatase * : Phosphohistidine phosphatase

:EC 3.10 (act on sulfur–nitrogen bonds)

* :

N-sulfoglucosamine sulfohydrolase In enzymology, a N-sulfoglucosamine sulfohydrolase () is an enzyme that catalyzes the chemical reaction :N-sulfo-D-glucosamine + H2O \rightleftharpoons D-glucosamine + sulfate Thus, the two substrates of this enzyme are N-sulfo-D-glucosamine a ...

* : Cyclamate sulfohydrolase

:EC 3.11 (act on carbon–phosphorus bonds)

* : Phosphonoacetaldehyde hydrolase * : Phosphonoacetate hydrolase * : Phosphonopyruvate hydrolase

:EC 3.12 (act on sulfur–sulfur bonds)

* : Trithionate hydrolase

:EC 3.13 (act on carbon–sulfur bonds)

* :

UDP-sulfoquinovose synthase UDP-sulfoquinovose synthase () is an enzyme that catalyzes the chemical reaction :UDP-glucose + sulfite \rightleftharpoons UDP-6-sulfoquinovose + H2O Thus, the two substrates of this enzyme are UDP-glucose and sulfite, whereas its two products ...

* : 2'-hydroxybiphenyl-2-sulfinate desulfinase * : 3-sulfinopropanoyl—CoA desulfinase * : Carbon disulfide hydrolase * : (CysO sulfur-carrier protein)-S-L-cysteine hydrolase * : Carbonyl sulfide hydrolase * : S-adenosyl-L-methionine hydrolase (adenosine-forming)

:Lyases (EC 4) ( Lyase)

:EC 4.1 (carbon–carbon lyases)

* :EC 4.1.1 **

Ornithine decarboxylase The enzyme ornithine decarboxylase (, ODC) catalyzes the decarboxylation of ornithine (a product of the urea cycle) to form putrescine. This reaction is the committed step in polyamine synthesis. In humans, this protein has 461 amino acids a ...

() **

Uridine monophosphate synthetase The enzyme Uridine monophosphate synthase (, UMPS) (orotate phosphoribosyl transferase and orotidine-5'-decarboxylase) catalyses the formation of uridine monophosphate (UMP), an energy-carrying molecule in many important biosynthetic pathways. In h ...

() **

Aromatic-L-amino-acid decarboxylase Aromatic L-amino acid decarboxylase (AADC or AAAD), also known as DOPA decarboxylase (DDC), tryptophan decarboxylase, and 5-hydroxytryptophan decarboxylase, is a lyase enzyme (), located in region 7p12.2-p12.1. Mechanism The enzyme uses pyrid ...

() **

RubisCO Ribulose-1,5-bisphosphate carboxylase-oxygenase, commonly known by the abbreviations RuBisCo, rubisco, RuBPCase, or RuBPco, is an enzyme () involved in the first major step of carbon fixation, a process by which atmospheric carbon dioxide is con ...

() * :EC 4.1.2 **

Fructose-bisphosphate aldolase Fructose-bisphosphate aldolase (), often just aldolase, is an enzyme catalyzing a reversible reaction that splits the aldol, fructose 1,6-bisphosphate, into the triose phosphates dihydroxyacetone phosphate (DHAP) and glyceraldehyde 3-phosphate ( ...

()

:EC 4.2 (carbon–oxygen lyases)

* :EC 4.2.1 ** Carbonic anhydrase () **

Tryptophan synthase Tryptophan synthase or tryptophan synthetase is an enzyme () that catalyses the final two steps in the biosynthesis of tryptophan. It is commonly found in Eubacteria, Archaebacteria, Protista, Fungi, and Plantae. However, it is absent from Anima ...

()

:EC 4.3 (carbon–nitrogen lyases)

* :EC 4.3.1 **

Phenylalanine ammonia-lyase The enzyme phenylalanine ammonia lyase (EC 4.3.1.24) catalyzes the conversion of L-phenylalanine to ammonia and ''trans''-cinnamic acid.: :L-phenylalanine = ''trans''-cinnamate + NH3 Phenylalanine ammonia lyase (PAL) is the first and committed ...

()

:EC 4.4 (carbon–sulfur lyases)

* :EC 4.4.1 **

Cystathionine gamma-lyase The enzyme cystathionine γ-lyase (EC 4.4.1.1, CTH or CSE; also cystathionase; systematic name L-cystathionine cysteine-lyase (deaminating; 2-oxobutanoate-forming)) breaks down cystathionine into cysteine, 2-oxobutanoate ( α-ketobutyrate), and ...

Cystathionine beta-lyase Cystathionine beta-lyase (), also commonly referred to as CBL or β-cystathionase, is an enzyme that primarily catalyzes the following α,β-elimination reaction Thus, the substrate of this enzyme is L-cystathionine, whereas its 3 products a ...

Leukotriene C4 synthase Leukotriene C4 synthase is an enzyme that in humans is encoded by the ''LTC4S'' gene. The protein encoded by this gene, LTC4S (or glutathione S-transferase II) is an enzyme that converts leukotriene A4 and glutathione to create leukotriene C4. T ...

:EC 4.5 (carbon–halide lyases)

* :EC 4.5.1 **

Dichloromethane dehalogenase Dichloromethane dehalogenase (EC 4.5.1.3; systematic name dichloromethane chloride-lyase (adding H2O; chloride-hydrolysing; formaldehyde-forming)) is a lyase enzyme that generates formaldehyde. : dichloromethane + H2O = formaldehyde + 2 chloride ...

Halohydrin dehalogenase A halohydrin dehalogenase is an enzyme involved in the bacterial degradation of vicinal halohydrin In organic chemistry a halohydrin (also a haloalcohol or β-halo alcohol) is a functional group in which a halogen and a hydroxyl are bonded to ...

:EC 4.6 (phosphorus–oxygen lyases)

* :EC 4.6.1 **

Adenylate cyclase Adenylate cyclase (EC 4.6.1.1, also commonly known as adenyl cyclase and adenylyl cyclase, abbreviated AC) is an enzyme with systematic name ATP diphosphate-lyase (cyclizing; 3′,5′-cyclic-AMP-forming). It catalyzes the following reaction: :A ...

() **

Guanylate cyclase Guanylate cyclase (EC 4.6.1.2, also known as guanyl cyclase, guanylyl cyclase, or GC; systematic name GTP diphosphate-lyase (cyclizing; 3′,5′-cyclic-GMP-forming)) is a lyase enzyme that converts guanosine triphosphate (GTP) to cyclic guanos ...

()

:Isomerases (EC 5) (
Isomerase Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed. The general form of such a reaction is as follows: A–B � ...
)

:EC 5.1 (racemases and epimerases)

* :EC 5.1.1 *

Amino-acid racemase In enzymology, an amino-acid racemase () is an enzyme that catalyzes the chemical reaction :an L-amino acid \rightleftharpoons a D-amino acid Hence, this enzyme has one substrate, L-amino acid, and one product, D-amino acid. This enzyme belon ...

: Phenylalanine racemase (ATP-hydrolysing) * Serine racemase * :EC 5.1.2 *

Mandelate racemase Mandelate racemase () is a bacterial enzyme which catalyzes the interconversion of the enantiomers of mandelate via an enol intermediate. This enzyme catalyses the following chemical reaction : (S)-mandelate \rightleftharpoons (R)-mandelate I ...

* :EC 5.1.3 *

UDP-glucose 4-epimerase The enzyme UDP-glucose 4-epimerase (), also known as UDP-galactose 4-epimerase or GALE, is a homodimeric epimerase found in bacterial, fungal, plant, and mammalian cells. This enzyme performs the final step in the Leloir pathway of galactose ...

* :EC 5.1.99 * Methylmalonyl CoA epimerase

:EC 5.2 (cis-trans-isomerases)

* :EC 5.2 *

FKBP FKBP, or FK506 binding protein, is a family of proteins that have prolyl isomerase activity and are related to the cyclophilins in function, though not in amino acid sequence. FKBPs have been identified in many eukaryotes, ranging from yeast to h ...

: FKBP1A *

FKBP1B Peptidyl-prolyl cis-trans isomerase FKBP1B is an enzyme that in humans is encoded by the ''FKBP1B'' gene. Function The protein encoded by this gene is a member of the immunophilin protein family, which play a role in immunoregulation and basic ...

FKBP2 FK506-binding protein 2 is a protein that in humans is encoded by the ''FKBP2'' gene. Function The protein encoded by this gene is a member of the immunophilin protein family, which play a role in immunoregulation and basic cellular processes i ...

FKBP3 FK506-binding protein 3 also known as FKBP25 is a protein that in humans is encoded by the ''FKBP3'' gene. Function The protein encoded by this gene is a member of the immunophilin protein family, which play a role in immunoregulation and basi ...

FKBP4 FK506-binding protein 4 is a protein that in humans is encoded by the ''FKBP4'' gene. Function The protein encoded by this gene is a member of the immunophilin protein family, which play a role in immunoregulation and basic cellular processes i ...

FKBP5 FK506 binding protein 5, also known as FKBP5, is a protein which in humans is encoded by the ''FKBP5'' gene. Function The protein encoded by this gene is a member of the immunophilin protein family, which play a role in immunoregulation and ba ...

FKBP6 FK506 binding protein 6, also known as FKBP6, is a human gene. The encoded protein shows structural homology to FKBP immunophilins, which bind to the immunosuppressants FK506 and rapamycin. FKBP6 is essential for homologous chromosome pairing in ...

FKBP8 FK506-binding protein 8 is a protein that in humans is encoded by the ''FKBP8'' gene. The protein encoded by this gene is a member of the immunophilin protein family, which play a role in immunoregulation and basic cellular processes involving p ...

* FKBP9 *

FKBP10 FK506-binding protein 10 is a protein that in humans is encoded by the ''FKBP10'' gene. The protein encoded by this gene belongs to the FKBP-type peptidyl-prolyl cis/trans isomerase family. It is located in endoplasmic reticulum and acts as mol ...

FKBPL FK506-binding protein like, also known as FKBPL, is a protein that in humans is encoded by the ''FKBPL'' gene. Function FKBPL has similarity to the immunophilin protein family, which play a role in immunoregulation and basic cellular processes ...

Cyclophilin Cyclophilins (CYPs) are a family of proteins named after their ability to bind to ciclosporin (cyclosporin A), an immunosuppressant which is usually used to suppress rejection after internal organ transplants. They are found in all domains of l ...

Parvulin ] Parvulin, a 92-amino acid protein discovered in E. coli in 1994,Rahfeld JU, Schierhorn A, Mann KH. (1994). A novel peptidyl-prolyl cis/trans isomerase from Escherichia coli. ''FEBS Lett'' 343:65. is the smallest known protein with prolyl isomera ...

Prolyl isomerase Prolyl isomerase (also known as peptidylprolyl isomerase or PPIase) is an enzyme () found in both prokaryotes and eukaryotes that interconverts the ''cis'' and ''trans'' isomers of peptide bonds with the amino acid proline. Proline has an ...

* 2-chloro-4-carboxymethylenebut-2-en-1,4-olide isomerase * Beta-carotene isomerase * Farnesol 2-isomerase * Furylfuramide isomerase * Linoleate isomerase *

Maleate isomerase In enzymology, a maleate isomerase (), or maleate cis-tran isomerase, is a member of the Asp/Glu racemase superfamily discovered in bacteria. It is responsible for catalyzing cis-trans isomerization of the C2-C3 double bond in maleate to produce ...

* Maleylacetoacetate isomerase * Maleylpyruvate isomerase *

* Photoisomerase * Prolycopene isomerase *

* Retinal isomerase * Retinol isomerase * Zeta-carotene isomerase

:EC 5.3 ( intramolecular
oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually u ...
s)

* :EC 5.3.3 ** Enoyl CoA isomerase () * :EC 5.3.4 **

Protein disulfide isomerase Protein disulfide isomerase (), or PDI, is an enzyme in the endoplasmic reticulum (ER) in eukaryotes and the periplasm of bacteria that catalyzes the formation and breakage of disulfide bonds between cysteine residues within proteins as the ...

()

:EC 5.4 (intramolecular
transferase A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of ...
s -- mutases)

* :EC 5.4.2 **

Phosphoglucomutase Phosphoglucomutase () is an enzyme that transfers a phosphate group on an α-D-glucose monomer from the 1 to the 6 position in the forward direction or the 6 to the 1 position in the reverse direction. More precisely, it facilitates the interconve ...

()

:EC 5.5 (intramolecular lyases)

:EC 5.99 (other isomerases)

* :EC 5.99.1 ** Topoisomerase (type I: , type II: )

:Ligases (EC 6) (
Ligase In biochemistry, a ligase is an enzyme that can catalyze the joining (ligation) of two large molecules by forming a new chemical bond. This is typically via hydrolysis of a small pendant chemical group on one of the larger molecules or the enzym ...
)

:EC 6.1 (form carbon–oxygen bonds)

6-carboxytetrahydropterin synthase * :EC 6.1.1 ** FARSB ()

:EC 6.2 (form carbon–sulfur bonds)

* : Acetate—CoA ligase * : Medium-chain acyl—CoA ligase * :

Long-chain-fatty-acid—CoA ligase The long chain fatty acyl-CoA ligase (or synthetase) is an enzyme () of the ligase family that activates the oxidation of complex fatty acids. Long chain fatty acyl-CoA synthetase catalyzes the formation of fatty acyl-CoA by a two-step process p ...

:EC 6.3 (form carbon–nitrogen bonds)

Glutamine synthetase Glutamine synthetase (GS) () is an enzyme that plays an essential role in the metabolism of nitrogen by catalyzing the condensation of glutamate and ammonia to form glutamine: Glutamate + ATP + NH3 → Glutamine + ADP + phosphate Glutam ...

() *

Argininosuccinate synthetase Argininosuccinate synthase or synthetase (ASS; ) is an enzyme that catalyzes the synthesis of argininosuccinic acid, argininosuccinate from citrulline and aspartic acid, aspartate. In humans, argininosuccinate synthase is encoded by the ''ASS ...

() * CTP synthase ()

:EC 6.4 (form carbon–carbon bonds)

Pyruvate carboxylase Pyruvate carboxylase (PC) encoded by the gene PC is an enzyme () of the ligase class that catalyzes (depending on the species) the physiologically irreversible carboxylation of pyruvate to form oxaloacetate (OAA). Image:Pyruvic-acid-2D-sk ...

() * Acetyl-CoA carboxylase ()

:EC 6.5 (form
phosphoric ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are ...
bonds)

DNA ligase DNA ligase is a specific type of enzyme, a ligase, () that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond. It plays a role in repairing single-strand breaks in duplex DNA in living organ ...

()

:EC 6.6 (form nitrogen–metal bonds)

{{DEFAULTSORT:List Of Enzymes

Enzymes Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

Enzymes

:Oxidoreductases (EC 1) (Oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually u ...)

:EC 1.1 (act on the CH-OH group of donors)

:EC 1.2 (act on the aldehyde or oxo group of donors)

:EC 1.3 (act on the CH-CH group of donors)

:EC 1.4 (act on the CH-NH2 group of donors)

:EC 1.5 (act on CH-NH group of donors)

:EC 1.6 (act on NADH or NADPH)

:EC 1.7 (act on other nitrogenous compounds as donors)

:EC 1.8 (act on a sulfur group of donors)

:EC 1.9 (act on a heme Heme, or haem (pronounced / hi:m/ ), is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver. In biochemical terms, heme is a coordination complex "consis ... group of donors)

:EC 1.10 (act on diphenols and related substances as donors)

:EC 1.12 (act on hydrogen as a donor)

:EC 1.13 (act on single donors with incorporation of molecular oxygen)

:EC 1.14 (act on paired donors with incorporation of molecular oxygen)

:EC 1.15 (act on superoxide radicals as acceptors)

:EC 1.16 (oxidize metal ions)

:EC 1.17 (act on CH or CH2 groups)

:EC 1.18 (act on iron–sulfur proteins as donors)

:EC 1.19 (act on reduced flavodoxin as donor)

:EC 1.20 (act on phosphorus or arsenic as donors)

:EC 1.21 (act on X-H and Y-H to form an X-Y bond)

:EC 1.97 (other oxidoreductases)

:Transferases (EC 2) (Transferase A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of ...)

:EC 2.1 (transfer one-carbon groups, Methylase Methyltransferases are a large group of enzymes that all methylate their substrates but can be split into several subclasses based on their structural features. The most common class of methyltransferases is class I, all of which contain a Rossm ...)

:EC 2.3 (acyltransferases)

:EC 2.4 (glycosyltransferases)

:EC 2.6 (transfer nitrogenous groups)

:EC 2.7 (transfer phosphorus-containing groups)

:EC 2.8 (transfer sulfur-containing groups)

:EC 2.9 (transfer selenium-containing groups)

:Hydrolases (EC 3) (Hydrolase Hydrolase is a class of enzyme that commonly perform as biochemical catalysts that use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules. Some common examples of hydrolase enzymes are este ...)

:EC 3.1 (act on ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ... bonds)

:EC 3.2 (act on sugars - glycosylases)

Function and clinical importance of some enzymes in category 3.2.1

Amylase

Lysozyme

Sucrase

Lactase

:EC 3.3 (act on ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ... bonds)

:EC 3.5 (act on carbon–nitrogen bonds, other than peptide bonds)

:EC 3.6 (act on acid anhydride An acid anhydride is a type of chemical compound derived by the removal of water molecules from an acid. In organic chemistry, organic acid anhydrides contain the functional group R(CO)O(CO)R'. Organic acid anhydrides often form when one equivale ...s)

:EC 3.7 (act on carbon–carbon bonds)

:EC 3.8 (act on halide bonds)

:EC 3.9 (act on phosphorus–nitrogen bonds)

:EC 3.10 (act on sulfur–nitrogen bonds)

:EC 3.11 (act on carbon–phosphorus bonds)

:EC 3.12 (act on sulfur–sulfur bonds)

:EC 3.13 (act on carbon–sulfur bonds)

:Lyases (EC 4) ( Lyase)

:EC 4.1 (carbon–carbon lyases)

:EC 4.2 (carbon–oxygen lyases)

:EC 4.3 (carbon–nitrogen lyases)

:EC 4.4 (carbon–sulfur lyases)

:EC 4.5 (carbon–halide lyases)

:EC 4.6 (phosphorus–oxygen lyases)

:Isomerases (EC 5) (Isomerase Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed. The general form of such a reaction is as follows: A–B � ...)

:EC 5.1 (racemases and epimerases)

:EC 5.2 (cis-trans-isomerases)

:EC 5.3 ( intramolecular oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually u ...s)

:EC 5.4 (intramolecular transferase A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of ...s -- mutases)

:EC 5.5 (intramolecular lyases)

:EC 5.99 (other isomerases)

:Ligases (EC 6) (Ligase In biochemistry, a ligase is an enzyme that can catalyze the joining (ligation) of two large molecules by forming a new chemical bond. This is typically via hydrolysis of a small pendant chemical group on one of the larger molecules or the enzym ...)

:EC 6.1 (form carbon–oxygen bonds)

:EC 6.2 (form carbon–sulfur bonds)

:EC 6.3 (form carbon–nitrogen bonds)

:EC 6.4 (form carbon–carbon bonds)

:EC 6.5 (form phosphoric ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are ... bonds)

:EC 6.6 (form nitrogen–metal bonds)

:Oxidoreductases (EC 1) (
Oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually u ...
)

:EC 1.4 (act on the CH-NH₂ group of donors)

:EC 1.9 (act on a
heme Heme, or haem (pronounced / hi:m/ ), is a precursor to hemoglobin, which is necessary to bind oxygen in the bloodstream. Heme is biosynthesized in both the bone marrow and the liver. In biochemical terms, heme is a coordination complex "consis ...
group of donors)

:EC 1.17 (act on CH or CH₂ groups)

:Transferases (EC 2) (
Transferase A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of ...
)

:EC 2.1 (transfer one-carbon groups,
Methylase Methyltransferases are a large group of enzymes that all methylate their substrates but can be split into several subclasses based on their structural features. The most common class of methyltransferases is class I, all of which contain a Rossm ...
)

:Hydrolases (EC 3) (
Hydrolase Hydrolase is a class of enzyme that commonly perform as biochemical catalysts that use water to break a chemical bond, which typically results in dividing a larger molecule into smaller molecules. Some common examples of hydrolase enzymes are este ...
)

:EC 3.1 (act on
ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...
bonds)

:EC 3.3 (act on
ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...
bonds)

:EC 3.6 (act on
acid anhydride An acid anhydride is a type of chemical compound derived by the removal of water molecules from an acid. In organic chemistry, organic acid anhydrides contain the functional group R(CO)O(CO)R'. Organic acid anhydrides often form when one equivale ...
s)

:Isomerases (EC 5) (
Isomerase Isomerases are a general class of enzymes that convert a molecule from one isomer to another. Isomerases facilitate intramolecular rearrangements in which bonds are broken and formed. The general form of such a reaction is as follows: A–B � ...
)

:EC 5.3 ( intramolecular
oxidoreductase In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor. This group of enzymes usually u ...
s)

:EC 5.4 (intramolecular
transferase A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of ...
s -- mutases)

:Ligases (EC 6) (
Ligase In biochemistry, a ligase is an enzyme that can catalyze the joining (ligation) of two large molecules by forming a new chemical bond. This is typically via hydrolysis of a small pendant chemical group on one of the larger molecules or the enzym ...
)

:EC 6.5 (form
phosphoric ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are ...
bonds)