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Carbon-carbon Lyases
This list contains a list of EC numbers for the fourth group, EC 4, lyases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. All official information is tabulated at the website of the committee. The database is developed and maintained by Andrew McDonald. EC 4.1: Carbon-Carbon Lyases EC 4.1.1: Carboxy-lyases * : pyruvate decarboxylase * : oxalate decarboxylase * EC 4.1.1.3: Now recognized to be two enzymes xaloacetate decarboxylase (Na+ extruding)and (oxaloacetate decarboxylase). * : acetoacetate decarboxylase * : acetolactate decarboxylase * : ''cis''-aconitate decarboxylase * : benzoylformate decarboxylase * : oxalyl-CoA decarboxylase * : malonyl-CoA decarboxylase * EC 4.1.1.10: Now included with , aspartate 4-decarboxylase * : aspartate 1-decarboxylase * : aspartate 4-decarboxylase * EC 4.1.1.13: deleted * : valine decarboxylase * : glutamate decarboxylase * : hydroxyglutama ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Commission Number
The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the corresponding enzyme-catalyzed reaction. EC numbers do not specify enzymes but enzyme-catalyzed reactions. If different enzymes (for instance from different organisms) catalyze the same reaction, then they receive the same EC number. Furthermore, through convergent evolution, completely different protein folds can catalyze an identical reaction (these are sometimes called non-homologous isofunctional enzymes) and therefore would be assigned the same EC number. By contrast, UniProt identifiers uniquely specify a protein by its amino acid sequence. Format of number Every enzyme code consists of the letters "EC" followed by four numbers separated by periods. Those numbers represent a progressively finer classification of the enzyme. Preliminary ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 and forms a homodimer. Reaction mechanism Lysine 69 on ornithine decarboxylase (ODC) binds the cofactor pyridoxal phosphate to form a Schiff base. Ornithine displaces the lysine to form a Schiff base attached to orthonine, which decarboxylates to form a quinoid intermediate. This intermediate rearranges to form a Schiff base attached to putrescine, which is attacked by lysine to release putrescine product and reform PLP-bound ODC. This is the first step and the rate-limiting step in humans for the production of polyamines, compounds required for cell division. Structure image:Ornithine Decarboxylase Publication View.png, 270px, 3D crystal structure of ornithine decarboxylase.; ; rendered viPyMOL The active form of ornithine decarboxylas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoenolpyruvate Carboxykinase (GTP)
Phosphoenolpyruvate carboxykinase (, PEPCK) is an enzyme in the lyase family used in the metabolic pathway of gluconeogenesis. It converts oxaloacetate into phosphoenolpyruvate and carbon dioxide. It is found in two forms, cytosolic and mitochondrial. Structure In humans there are two isoforms of PEPCK; a cytosolic form (SwissProt P35558) and a mitochondrial isoform (SwissProt Q16822) which have 63.4% sequence identity. The cytosolic form is important in gluconeogenesis. However, there is a known transport mechanism to move PEP from the mitochondria to the cytosol, using specific membrane transport proteins. PEP transport across the inner mitochondrial membrane involves the mitochondrial tricarboxylate transport protein and to a lesser extent the adenine nucleotide carrier. The possibility of a PEP/pyruvate transporter has also been put forward. X-ray structures of PEPCK provide insight into the structure and the mechanism of PEPCK enzymatic activity. The mitochondri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoenolpyruvate Carboxylase
Phosphoenolpyruvate carboxylase (also known as PEP carboxylase, PEPCase, or PEPC; , PDB ID: 3ZGE) is an enzyme in the family of carboxy-lyases found in plants and some bacteria that catalyzes the addition of bicarbonate (HCO3−) to phosphoenolpyruvate (PEP) to form the four-carbon compound oxaloacetate and inorganic phosphate: :PEP + HCO3− → oxaloacetate + Pi This reaction is used for carbon fixation in CAM (crassulacean acid metabolism) and organisms, as well as to regulate flux through the citric acid cycle (also known as Krebs or TCA cycle) in bacteria and plants. The enzyme structure and its two step catalytic, irreversible mechanism have been well studied. PEP carboxylase is highly regulated, both by phosphorylation and allostery. Enzyme structure The PEP carboxylase enzyme is present in plants and some types of bacteria, but not in fungi or animals (including humans). The genes vary between organisms, but are strictly conserved around the active and allosteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantothenoylcysteine Decarboxylase
The enzyme pantothenoylcysteine decarboxylase () catalyzes the chemical reaction :N- R)-pantothenoylL-cysteine \rightleftharpoons pantetheine + CO2 This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is N- R)-pantothenoylL-cysteine carboxy-lyase (pantetheine-forming). Other names in common use include pantothenylcysteine decarboxylase, and N- R)-pantothenoylL-cysteine carboxy-lyase. This enzyme participates in pantothenate and coa biosynthesis Pantothenic acid, also called vitamin B5 is a water-soluble B vitamin and therefore an essential nutrient. All animals require pantothenic acid in order to synthesize coenzyme A (CoA) – essential for fatty acid metabolism – as well as to, .... References * EC 4.1.1 Enzymes of unknown structure {{4.1-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfoalanine Decarboxylase
The enzyme sulfinoalanine decarboxylase () catalyzes the chemical reaction :3-sulfino-L-alanine \rightleftharpoons hypotaurine + CO2 Hence, this enzyme has one substrate, 3-sulfino-L-alanine (also known as Cysteine sulfinic acid), and two products, hypotaurine and CO2. This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is 3-sulfino-L-alanine carboxy-lyase (hypotaurine-forming). Other names in common use include cysteine-sulfinate decarboxylase, L-cysteinesulfinic acid decarboxylase, cysteine-sulfinate decarboxylase, CADCase/CSADCase, CSAD, cysteic decarboxylase, cysteinesulfinic acid decarboxylase, cysteinesulfinate decarboxylase, sulfoalanine decarboxylase, and 3-sulfino-L-alanine carboxy-lyase. This enzyme participates in taurine metabolism. It employs one cofactor, pyridoxal phosphate Pyridoxal phosphate (PLP, pyridoxal 5'- phosphate, P5P), the active form of vit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 pyridoxal phosphate (PLP), the active form of vitamin B6, as a cofactor. PLP is essential to the mechanism of decarboxylation in AADC. In the active enzyme, PLP is bound to lysine-303 of AADC as a Schiff base. Upon substrate binding, Lys-303 is displaced by the substrate's amine. This positions the carboxylate of the substrate within the active site such that decarboxylation is favored. Decarboxylation of the substrate produces a quinonoid intermediate, which is subsequently protonated to produce a Schiff base adduct of PLP and the decarboxylated product. Lys-303 can then regenerate the original Schiff base, releasing the product while retaining PLP. Probing this PLP-catalyzed decarboxylation, it has been discovered that there is a difference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tyrosine Decarboxylase
The enzyme tyrosine decarboxylase () catalyzes the chemical reaction :L-tyrosine \rightleftharpoons tyramine + CO2 Hence, this enzyme has one substrate, L-tyrosine, and two products, tyramine and carbon dioxide. This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is L-tyrosine carboxy-lyase (tyramine-forming). Other names in common use include L-tyrosine decarboxylase, L-(−)-tyrosine apodecarboxylase, and L-tyrosine carboxy-lyase. This enzyme participates in tyrosine metabolism and alkaloid biosynthesis. It employs one cofactor, pyridoxal phosphate Pyridoxal phosphate (PLP, pyridoxal 5'-phosphate, P5P), the active form of vitamin B6, is a coenzyme in a variety of enzymatic reactions. The International Union of Biochemistry and Molecular Biology has catalogued more than 140 PLP-dependent ac .... References * EC 4.1.1 Pyridoxal phosphate enzymes Enzymes of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aminobenzoate Decarboxylase
The enzyme aminobenzoate decarboxylase () catalyzes the chemical reaction :4(or 2)-aminobenzoate \rightleftharpoons aniline + CO2 Thus, the two substrates of this enzyme are 4-aminobenzoate and 2-aminobenzoate, whereas its two products are aniline and CO2. This enzyme belongs to the family of lyase In biochemistry, a lyase is an enzyme that catalyzes the breaking (an elimination reaction) of various chemical bonds by means other than hydrolysis (a substitution reaction) and oxidation, often forming a new double bond or a new ring structure. ...s, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is aminobenzoate carboxy-lyase (aniline-forming). It employs one cofactor, pyridoxal phosphate. References * EC 4.1.1 Pyridoxal phosphate enzymes Enzymes of unknown structure {{4.1-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orotidine-5'-phosphate Decarboxylase
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 humans, the gene that codes for this enzyme is located on the long arm of chromosome 3 (3q13). Structure and function This bifunctional enzyme has two main domains, an orotate phosphoribosyltransferase (OPRTase, ) subunit and an orotidine-5’-phosphate decarboxylase (ODCase, ) subunit. These two sites catalyze the last two steps of the de novo uridine monophosphate (UMP) biosynthetic pathway. After addition of ribose-P to orotate by OPRTase to form orotidine-5’-monophosphate (OMP), OMP is decarboxylated to form uridine monophosphate by ODCase. In microorganisms, these two domains are separate proteins, but, in multicellular eukaryotes, the two catalytic sites are expressed on a single protein, uridine monophosphate synthase. UMPS ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histidine Decarboxylase
The enzyme histidine decarboxylase (, HDC) is transcribed on chromosome 15, region 21.2, and catalyzes the decarboxylation of histidine to form histamine. In mammals, histamine is an important biogenic amine with regulatory roles in neurotransmission, gastric acid secretion and immune response. Histidine decarboxylase is the sole member of the histamine synthesis pathway, producing histamine in a one-step reaction. Histamine cannot be generated by any other known enzyme. HDC is therefore the primary source of histamine in most mammals and eukaryotes. The enzyme employs a pyridoxal 5'-phosphate (PLP) cofactor, in similarity to many amino acid decarboxylases. Eukaryotes, as well as gram-negative bacteria share a common HDC, while gram-positive bacteria employ an evolutionarily unrelated pyruvoyl-dependent HDC. In humans, histidine decarboxylase is encoded by the ''HDC'' gene. Structure Histidine decarboxylase is a group II pyridoxal-dependent decarboxylase, along with aromati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphoribosylaminoimidazole Carboxylase
The enzyme Phosphoribosylaminoimidazole carboxylase, or AIR carboxylase () is involved in nucleotide biosynthesis and in particular in purine biosynthesis. It catalyzes the conversion of 5'-phosphoribosyl-5-aminoimidazole ("AIR") into 5'-phosphoribosyl-4-carboxy-5-aminoimidazole ("CAIR") as described in the reaction: :5-aminoimidazole ribonucleotide + CO2 \rightleftharpoons 5'-phosphoribosyl-4-carboxy-5-aminoimidazole + 2 H+ In plants and fungi Phosphoribosylaminoimidazole carboxylase is a fusion protein in plants and fungi, but consists of two non-interacting proteins in bacteria, PurK and PurE. The crystal structure of PurE indicates a unique quaternary structure that confirms the octameric nature of the enzyme. In ''Escherichia coli'' In the bacterium ''Escherichia coli'' the reaction is catalyzed in two steps carried out by two separate enzymes, PurK and PurE. PurK, ''N''5-carboxyaminoimidazole ribonucleotide synthetase, catalyzes the conversion of 5-aminoimidazole rib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
