hydrolysis
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Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and
solvation Solvation (or dissolution) describes the interaction of a solvent with Solution (chemistry), dissolved molecules. Both ionized and uncharged molecules interact strongly with a solvent, and the strength and nature of this interaction influence ma ...
reactions in which water is the
nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...
. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a
carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or may ...
is broken into its component sugar molecules by hydrolysis (e.g.,
sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...
being broken down into
glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis f ...
and
fructose Fructose, or fruit sugar, is a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbe ...
), this is recognized as
saccharification In chemistry, saccharification is a term for denoting any chemical change wherein a monosaccharide molecule remains intact after becoming unbound from another saccharide. For example, when a carbohydrate is broken into its component sugar molecul ...
. Hydrolysis reactions can be the reverse of a
condensation reaction In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are Combination reaction, combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reacti ...
in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water.


Types

Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and water molecule to split into two parts. In such reactions, one fragment of the target molecule (or parent molecule) gains a
hydrogen ion A hydrogen ion is created when a hydrogen atom loses or gains an electron. A positively charged hydrogen ion (or proton) can readily combine with other particles and therefore is only seen isolated when it is in a gaseous state or a nearly particle ...
. It breaks a chemical bond in the compound.


Salts

A common kind of hydrolysis occurs when a
salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of Salt (chemistry), salts; salt in the form of a natural crystallinity, crystalline mineral is known as rock salt or halite. ...
of a
weak acid Acid strength is the tendency of an acid An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen ion, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis a ...

weak acid
or
weak base A weak base is a base (chemistry), base that, upon dissolution in water, does not dissociate completely, so that the resulting aqueous solution contains only a small proportion of hydroxide ions and the concerned basic radical, and a large proporti ...
(or both) is dissolved in water. Water spontaneously ionizes into hydroxide anions and
hydronium cations
hydronium cations
. The salt also dissociates into its constituent anions and cations. For example,
sodium acetate Sodium acetate, CH3COONa, also abbreviated Na O Ac, is the sodium salt of acetic acid. This colorless deliquescent Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or ad ...
dissociates in water into
sodium Sodium is a chemical element with the Symbol (chemistry), symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the ...

sodium
and
acetate An acetate is a salt (chemistry), salt formed by the combination of acetic acid with a base (e.g. Alkali metal, alkaline, Alkaline earth metal, earthy, Transition metal, metallic, nonmetallic or radical Radical (chemistry), base). "Acetate" als ...

acetate
ions. Sodium ions react very little with the hydroxide ions whereas the acetate ions combine with hydronium ions to produce
acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bond ...

acetic acid
. In this case the net result is a relative excess of hydroxide ions, yielding a basic solution.
Strong acids Acid strength is the tendency of an acid, symbolised by the chemical formula HA, to dissociate into a hydron (chemistry), proton, H+, and an anion, A-. The Dissociation (chemistry), dissociation of a strong acid in solution is effectively comple ...
also undergo hydrolysis. For example, dissolving
sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen ...

sulfuric acid
() in water is accompanied by hydrolysis to give
hydronium In chemistry, hydronium (hydroxonium in traditional British English) is the common name for the aqueous cation , the type of oxonium ion produced by protonation of water. It is often viewed as the positive ion present when an Arrhenius acid is di ...

hydronium
and
bisulfate The sulfate or sulphate ion is a polyatomic ion, polyatomic anion with the empirical formula . Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salt (chemistry), ...
, the sulfuric acid's
conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory, is a chemical compound formed when an acid protonation, donates a proton () to a base (chemistry), base—in other words, it is a base with a hydrogen ion added to it, as in the ...
. For a more technical discussion of what occurs during such a hydrolysis, see
Brønsted–Lowry acid–base theory The Brønsted–Lowry theory (also called proton theory of acids and bases) is an acid–base reaction theory which was proposed independently by Johannes Nicolaus Brønsted and Thomas Martin Lowry in 1923. The fundamental concept of this theory ...
.


Esters and amides

Acid–base-catalysed hydrolyses are very common; one example is the hydrolysis of
amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a chemical compound, compound with the general formula , where R, R', and R″ represent organic compound, organic functional group, groups or hydrogen atoms ...

amide
s or
ester In chemistry, an ester is a chemical compound, 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 ...

ester
s. Their hydrolysis occurs when the
nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...
(a nucleus-seeking agent, e.g., water or hydroxyl ion) attacks the carbon of the
carbonyl group In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double bond, double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound c ...

carbonyl group
of the
ester In chemistry, an ester is a chemical compound, 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 ...

ester
or
amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a chemical compound, compound with the general formula , where R, R', and R″ represent organic compound, organic functional group, groups or hydrogen atoms ...

amide
. In an aqueous base, hydroxyl ions are better nucleophiles than polar molecules such as water. In acids, the carbonyl group becomes protonated, and this leads to a much easier nucleophilic attack. The products for both hydrolyses are compounds with
carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with substituent, R referring to the alkyl, alkenyl, aryl, or other group. ...
groups. Perhaps the oldest commercially practiced example of ester hydrolysis is
saponification Saponification is a process of converting esters into soap, soaps and Alcohol (chemistry), alcohols by the action of aqueous alkali (for example, aqueous sodium hydroxide solutions). Soaps are salt (chemistry), salts of fatty acids, which in turn a ...

saponification
(formation of soap). It is the hydrolysis of a
triglyceride A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''wikt:tri-#Prefix, tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other ...
(fat) with an aqueous base such as
sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive, caustic base (c ...
(NaOH). During the process,
glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
is formed, and the
fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated and unsaturated compounds#Organic chemistry, saturated or unsaturated. Most naturally occurring fatty acids have an B ...
s react with the base, converting them to salts. These salts are called soaps, commonly used in households. In addition, in living systems, most biochemical reactions (including ATP hydrolysis) take place during the catalysis of
enzyme 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 ...
s. The catalytic action of enzymes allows the hydrolysis of
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabo ...
s, fats, oils, and
carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or may ...
s. As an example, one may consider
protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurri ...
s (enzymes that aid
digestion Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intest ...
by causing hydrolysis of
peptide bond In organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that c ...
s in
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabo ...
s). They catalyze the hydrolysis of interior peptide bonds in peptide chains, as opposed to
exopeptidase An exopeptidase is any peptidase A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which en ...
s (another class of enzymes, that catalyze the hydrolysis of terminal peptide bonds, liberating one free amino acid at a time). However, proteases do not catalyze the hydrolysis of all kinds of proteins. Their action is stereo-selective: Only proteins with a certain tertiary structure are targeted as some kind of orienting force is needed to place the amide group in the proper position for catalysis. The necessary contacts between an enzyme and its substrates (proteins) are created because the enzyme folds in such a way as to form a crevice into which the substrate fits; the crevice also contains the catalytic groups. Therefore, proteins that do not fit into the crevice will not undergo hydrolysis. This specificity preserves the integrity of other proteins such as
hormone A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and beh ...
s, and therefore the biological system continues to function normally. Upon hydrolysis, an
amide In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a chemical compound, compound with the general formula , where R, R', and R″ represent organic compound, organic functional group, groups or hydrogen atoms ...

amide
converts into a
carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with substituent, R referring to the alkyl, alkenyl, aryl, or other group. ...
and an
amine In chemistry, amines (, ) are chemical compound, compounds and functional groups that contain a base (chemistry), basic nitrogen atom with a lone pair. Amines are formally derivative (chemistry), derivatives of ammonia (), wherein one or mo ...
or
ammonia Ammonia is an inorganic chemical compound, compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a dis ...
(which in the presence of acid are immediately converted to ammonium salts). One of the two oxygen groups on the carboxylic acid are derived from a water molecule and the amine (or ammonia) gains the hydrogen ion. The hydrolysis of
peptides Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called Protein, proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapepti ...
gives
amino acid Amino acids are organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bonds. Due to carbon's ability to Catenation, catenate (form chains with ot ...
s. Many
polyamide A polyamide is a polymer A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemical substance, substance or material consisting of very large molecules called macromolecules, composed of many Repeat unit, re ...
polymers such as nylon 6,6 hydrolyze in the presence of strong acids. The process leads to
depolymerization Depolymerization (or depolymerisation) is the process of converting a polymer A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemical substance, substance or material consisting of very large molecules cal ...
. For this reason nylon products fail by fracturing when exposed to small amounts of acidic water. Polyesters are also susceptible to similar
polymer degradation Polymer degradation is the reduction in the physical properties of a polymer A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemical substance, substance or material consisting of very large molecules c ...
reactions. The problem is known as
environmental stress cracking Environmental Stress Cracking (ESC) is one of the most common causes of unexpected brittle A material is brittle if, when subjected to stress (physics), stress, it fractures with little elastic deformation and without significant plastic ...
.


ATP

Hydrolysis is related to
energy metabolism Bioenergetics is a field in biochemistry Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three ...
and storage. All living cells require a continual supply of energy for two main purposes: the
biosynthesis Biosynthesis is a multi-step, enzyme 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 ...
of micro and macromolecules, and the active transport of ions and molecules across cell membranes. The energy derived from the
oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction ...
of nutrients is not used directly but, by means of a complex and long sequence of reactions, it is channeled into a special energy-storage molecule,
adenosine triphosphate Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all ...
(ATP). The ATP molecule contains
pyrophosphate In chemistry, pyrophosphates are phosphorus oxyanions that contain two phosphorus atoms in a P–O–P linkage. A number of pyrophosphate salts exist, such as disodium pyrophosphate (Na2H2P2O7) and tetrasodium pyrophosphate (Na4P2O7), among other ...
linkages (bonds formed when two phosphate units are combined) that release energy when needed. ATP can undergo hydrolysis in two ways: Firstly, the removal of terminal phosphate to form
adenosine diphosphate Adenosine diphosphate (ADP), also known as adenosine pyrophosphate (APP), is an important organic compound in metabolism and is essential to the flow of energy in living cells (biology), cells. ADP consists of three important structural components: ...
(ADP) and inorganic phosphate, with the reaction: : ATP + H2O -> ADP + P_ Secondly, the removal of a terminal diphosphate to yield
adenosine monophosphate Adenosine monophosphate (AMP), also known as 5'-adenylic acid, is a nucleotide. AMP consists of a phosphate group, the sugar ribose, and the nucleobase adenine; it is an ester of phosphoric acid and the nucleoside adenosine. As a substituent it t ...
(AMP) and
pyrophosphate In chemistry, pyrophosphates are phosphorus oxyanions that contain two phosphorus atoms in a P–O–P linkage. A number of pyrophosphate salts exist, such as disodium pyrophosphate (Na2H2P2O7) and tetrasodium pyrophosphate (Na4P2O7), among other ...
. The latter usually undergoes further cleavage into its two constituent phosphates. This results in biosynthesis reactions, which usually occur in chains, that can be driven in the direction of synthesis when the phosphate bonds have undergone hydrolysis.


Polysaccharides

Monosaccharide Monosaccharides (from Greek language, Greek ''wikt:μόνος, monos'': single, ''wikt:σάκχαρ, sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates a ...
s can be linked together by
glycosidic bond A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal group ...
s, which can be cleaved by hydrolysis. Two, three, several or many monosaccharides thus linked form
disaccharide A disaccharide (also called a double sugar or ''biose'') is the sugar formed when two monosaccharides are joined by glycosidic linkage. Like monosaccharides, disaccharides are simple sugars solubility, soluble in water. Three common examples are s ...
s,
trisaccharide ''Trisaccharides'' are oligosaccharides composed of three monosaccharides with two glycosidic bonds connecting them. Similar to the disaccharides, each glycosidic bond can be formed between any hydroxyl group on the component monosaccharides. Even ...
s,
oligosaccharide An oligosaccharide (/ˌɑlɪgoʊˈsækəˌɹaɪd/; from the Greek wikt:ὀλίγος#Ancient Greek, ὀλίγος ''olígos'', "a few", and σάκχαρ ''sácchar'', "sugar") is a carbohydrate, saccharide polymer containing a small number (typical ...
s, or
polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic bond, glycosidic linkages. This carbohydrate c ...
s, respectively. Enzymes that hydrolyze glycosidic bonds are called "
glycoside hydrolase Glycoside hydrolases (also called glycosidases or glycosyl hydrolases) catalyze the hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substituti ...
s" or "glycosidases". The best-known disaccharide is
sucrose Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula . For human consumption, sucrose is extracted and refined ...
(table sugar). Hydrolysis of sucrose yields
glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis f ...
and
fructose Fructose, or fruit sugar, is a ketonic simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbe ...
.
Invertase Invertase is an enzyme that catalyst, catalyzes the hydrolysis (breakdown) of sucrose (table sugar) into fructose and glucose. Alternative names for invertase include , saccharase, glucosucrase, beta-h-fructosidase, beta-fructosidase, invertin, su ...
is a
sucrase Sucrase is a digestive enzyme 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 subs ...
used industrially for the hydrolysis of sucrose to so-called
invert sugar Inverted sugar syrup, also called invert syrup, invert sugar, simple syrup, sugar syrup, sugar water, bar syrup, syrup United States Pharmacopeia, USP, or sucrose inversion, is a syrup mixture of the monosaccharides glucose and fructose, that ...
.
Lactase Lactase is an enzyme 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 substra ...
is essential for digestive hydrolysis of
lactose Lactose is a disaccharide sugar synthesized by galactose and glucose subunits and has the molecular formula C12H22O11. Lactose makes up around 2–8% of milk (by mass). The name comes from ' (gen. '), the Latin word for milk, plus the suffix ''-o ...
in milk; many adult humans do not produce lactase and cannot digest the lactose in milk. The hydrolysis of polysaccharides to soluble sugars can be recognized as
saccharification In chemistry, saccharification is a term for denoting any chemical change wherein a monosaccharide molecule remains intact after becoming unbound from another saccharide. For example, when a carbohydrate is broken into its component sugar molecul ...
. Malt made from
barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia Eurasia (, ) is the largest continental area o ...
is used as a source of β-amylase to break down
starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diets, ...
into the disaccharide
maltose } Maltose ( or ), also known as maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4) glycosidic bond, bond. In the isomer isomaltose, the two glucose molecules are joined with an α(1→6) bond. Ma ...
, which can be used by yeast to produce beer. Other
amylase An amylase () is an enzyme that catalysis, 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 ...
enzymes may convert starch to glucose or to oligosaccharides.
Cellulose Cellulose is an organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bonds. Due to carbon's ability to Catenation, catenate (form chains with other ...
is first hydrolyzed to cellobiose by
cellulase Cellulase (EC 3.2.1.4; systematic name 4-β-D-glucan 4-glucanohydrolase) is any of several enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccharide ...
and then cellobiose is further hydrolyzed to
glucose Glucose is a simple sugar with the Chemical formula#Molecular formula, molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis f ...
by
beta-glucosidase β-Glucosidase (EC 3.2.1.21; systematic name β-D-glucoside glucohydrolase) is an enzyme that catalyses the following reaction: : Hydrolysis of terminal, non-reducing β-D-glucosyl residues with release of β-D-glucose Structure β-Glucosidase ...
.
Ruminants Ruminants (suborder Ruminantia) are ungulate, hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by Enteric fermentation, fermenting it in a specialized stomach prior to digestion, principally ...
such as cows are able to hydrolyze cellulose into cellobiose and then glucose because of
symbiotic Symbiosis (from Ancient Greek, Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different Organism, biological organisms, be it Mutualism (biolog ...
bacteria that produce cellulases.


Metal aqua ions

Metal ions are
Lewis acid A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty Non-bonding orbital, orbital which is capable of accepting an electron pair from a Lewis Base (chemistry), base to form a Lewis a ...
s, and in
aqueous solution An aqueous solution is a Solution (chemistry), solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, or sodium chloride (NaCl), ...
they form
metal aquo complex In chemistry, metal aquo complexes are coordination compounds containing metal ions with only water as a ligand. These complexes are the predominant Chemical species, species in aqueous solutions of many metal Salt (chemistry), salts, such as meta ...
es of the general formula . The aqua ions undergo hydrolysis, to a greater or lesser extent. The first hydrolysis step is given generically as :M(H2O)_\mathit^ + H2O <=> M(H2O)_(OH)^ + H3O+ Thus the aqua
cation An ion () is an atom or molecule with a net electric charge, electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be po ...
s behave as acids in terms of
Brønsted–Lowry acid–base theory The Brønsted–Lowry theory (also called proton theory of acids and bases) is an acid–base reaction theory which was proposed independently by Johannes Nicolaus Brønsted and Thomas Martin Lowry in 1923. The fundamental concept of this theory ...
. This effect is easily explained by considering the
inductive effect In chemistry, the inductive effect in a molecule is a local change in the electron density due to electron-withdrawing or electron-donating groups elsewhere in the molecule, resulting in a permanent dipole in a bond. It is present in a sigma bond, ...
of the positively charged metal ion, which weakens the bond of an attached water molecule, making the liberation of a proton relatively easy. The
dissociation constant In chemistry, biochemistry, and pharmacology, a dissociation constant (K_D) is a specific type of equilibrium constant that measures the propensity of a larger object to separate (dissociate) reversibly into smaller components, as when a compl ...
, pKa, for this reaction is more or less linearly related to the charge-to-size ratio of the metal ion. Ions with low charges, such as are very weak acids with almost imperceptible hydrolysis. Large divalent ions such as , , and have a pKa of 6 or more and would not normally be classed as acids, but small divalent ions such as undergo extensive hydrolysis. Trivalent ions like and are weak acids whose pKa is comparable to that of
acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon chemical bond, bond ...

acetic acid
. Solutions of salts such as or in water are noticeably
acidic In computer science, ACID (Atomicity (database systems), atomicity, Consistency (database systems), consistency, Isolation (database systems), isolation, Durability (database systems), durability) is a set of properties of database transactions i ...
; the hydrolysis can be suppressed by adding an acid such as
nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...
, making the solution more acidic. Hydrolysis may proceed beyond the first step, often with the formation of polynuclear species via the process of olation. Some "exotic" species such as are well characterized. Hydrolysis tends to proceed as pH rises leading, in many cases, to the precipitation of a hydroxide such as or . These substances, major constituents of
bauxite Bauxite is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH ...
, are known as
laterite Laterite is both a soil and a rock type rich in iron and aluminium and is commonly considered to have formed in hot and wet tropical areas. Nearly all laterites are of rusty-red coloration, because of high iron oxide content. They develop by ...
s and are formed by leaching from rocks of most of the ions other than aluminium and iron and subsequent hydrolysis of the remaining aluminium and iron.


Mechanism strategies

Acetal In organic chemistry, an acetal is a functional group with the connectivity . Here, the R groups can be organic fragments (a carbon atom, with arbitrary other atoms attached to that) or hydrogen, while the R' groups must be organic fragments no ...
s,
imine In organic chemistry, an imine ( or ) is a functional group or organic compound containing a carbon–nitrogen double bond (). The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bon ...
s, and
enamine An enamine is an unsaturated compound derived by the condensation of an aldehyde or ketone with a secondary amine. Enamines are versatile intermediates. : The word "enamine" is derived from the affix ''en''-, used as the suffix of alkene, and the ...
s can be converted back into
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 bon ...
s by treatment with excess water under acid-catalyzed conditions: ; ; .


See also

*
Acid hydrolysis In organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that con ...
*
Adenosine triphosphate Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cell (biology), cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all ...
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Alkaline hydrolysis (body disposal) Alkaline hydrolysis (also called biocremation, resomation, flameless cremation, aquamation or water cremation) is a process for the disposal of human and pet remains using lye A lye is a metal hydroxide traditionally obtained by leaching woo ...
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Catabolism Catabolism () is the set of Metabolism, metabolic pathways that breaks down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions. Catabolism breaks down large molecules (such as polysacchari ...
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Condensation reaction In organic chemistry, a condensation reaction is a type of chemical reaction in which two molecules are Combination reaction, combined to form a single molecule, usually with the loss of a small molecule such as water. If water is lost, the reacti ...
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Dehydration reaction In chemistry, a dehydration reaction is a chemical reaction that involves the loss of water from the reacting molecule or ion. Dehydration reactions are common processes, the reverse of a hydration reaction. Dehydration reactions in organic che ...
* Hydrolysis constant *
Inhibitor protein The inhibitor protein (IP) is situated in the mitochondrial A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, mem ...
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Polymer degradation Polymer degradation is the reduction in the physical properties of a polymer A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemical substance, substance or material consisting of very large molecules c ...
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Proteolysis Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called proteases, ...
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Saponification Saponification is a process of converting esters into soap, soaps and Alcohol (chemistry), alcohols by the action of aqueous alkali (for example, aqueous sodium hydroxide solutions). Soaps are salt (chemistry), salts of fatty acids, which in turn a ...
* Sol–gel polymerisation *
Solvolysis In chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, struct ...
* Thermal hydrolysis


References

{{Authority control Chemical reactions Equilibrium chemistry