Hydrolase is a class of

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 ...

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

esterase An esterase is a hydrolase enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis. A wide range of different esterases exist that differ in their substrate specificity, their protein structure ...

s including

lipase Lipase ( ) is a family of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; however, these are usually ...

phosphatase In biochemistry, a phosphatase is an enzyme that uses water to cleave a phosphoric acid monoester into a phosphate ion and an alcohol. Because a phosphatase enzyme catalyzes the hydrolysis of its substrate, it is a subcategory of hydrolase ...

glycosidases Glycoside hydrolases (also called glycosidases or glycosyl hydrolases) catalyze Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the rea ...

peptidases 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 form ...

, and nucleosidases.

Esterase An esterase is a hydrolase enzyme that splits esters into an acid and an alcohol in a chemical reaction with water called hydrolysis. A wide range of different esterases exist that differ in their substrate specificity, their protein structure ...

s cleave ester bonds in

lipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids in ...

s and phosphatases cleave

phosphate group In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthophosphoric acid . The phosphate or orthophosphate ion is derived from phosph ...

s off molecules. An example of crucial esterase is acetylcholine esterase, which assists in transforming the neuron impulse into the acetate group after the hydrolase breaks the

acetylcholine Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Par ...

into

choline Choline is an essential nutrient for humans and many other animals. Choline occurs as a cation that forms various salts (X− in the depicted formula is an undefined counteranion). Humans are capable of some ''de novo synthesis'' of choline but r ...

and

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main componen ...

. Acetic acid is an important metabolite in the body and a critical intermediate for other reactions such as

glycolysis Glycolysis is the metabolic pathway that converts glucose () into pyruvate (). The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH ...

. Lipases hydrolyze

glyceride Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids, and are generally very hydrophobic. Glycerol has three hydroxyl functional groups, which can be esterified with one, two, or three fatty acids ...

s. Glycosidases cleave sugar molecules off carbohydrates and peptidases hydrolyze

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. Nucleosidases hydrolyze the bonds of

nucleotide Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecu ...

s. Hydrolase enzymes are important for the body because they have degradative properties. In lipids, lipases contribute to the breakdown of fats and lipoproteins and other larger molecules into smaller molecules like fatty acids and

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 ...

. Fatty acids and other small molecules are used for synthesis and as a source of energy. 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 fields: structural biology, enzymology and ...

, a ''hydrolase'' is an enzyme that catalyzes 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 substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysi ...

of a

chemical bond A chemical bond is a lasting attraction between atoms or ions that enables the formation of molecules and crystals. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds, or through the sharing of ...

. For example, any enzyme that catalyzes the following

reaction Reaction may refer to a process or to a response to an action, event, or exposure: Physics and chemistry *Chemical reaction *Nuclear reaction * Reaction (physics), as defined by Newton's third law *Chain reaction (disambiguation). Biology and m ...

is a hydrolase: :A–B + H₂O → A–OH + B–H where A–B represents a chemical bond of unspecified molecules.

Nomenclature

Systematic names of hydrolases are formed as " substrate hydrolase." However, common names are typically in the form "''substrate base''." For example, a

nuclease A nuclease (also archaically known as nucleodepolymerase or polynucleotidase) is an enzyme capable of cleaving the phosphodiester bonds between nucleotides of nucleic acids. Nucleases variously effect single and double stranded breaks in their t ...

is a hydrolase that cleaves

nucleic acid Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main ...

Classification

Hydrolases are classified as EC 3 in the EC number classification of enzymes. Hydrolases can be further classified into several subclasses, based upon the bonds they act upon: * EC 3.1:

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 ...

bonds (

phosphodiesterase A phosphodiesterase (PDE) is an enzyme that breaks a phosphodiester bond. Usually, ''phosphodiesterase'' refers to cyclic nucleotide phosphodiesterases, which have great clinical significance and are described below. However, there are many ot ...

) * EC 3.2: sugars (

DNA glycosylase DNA glycosylases are a family of enzymes involved in base excision repair, classified under EC number EC 3.2.2. Base excision repair is the mechanism by which damaged bases in DNA are removed and replaced. DNA glycosylases catalyze the first st ...

glycoside hydrolase Glycoside hydrolases (also called glycosidases or glycosyl hydrolases) catalyze the hydrolysis of glycosidic bonds in complex sugars. They are extremely common enzymes with roles in nature including degradation of biomass such as cellulose (cel ...

) * EC 3.3:

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 ...

bonds * EC 3.4:

s ( Proteases/peptidases) * EC 3.5: carbon-nitrogen bonds, other than peptide bonds * EC 3.6

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 (

acid anhydride hydrolases Acid anhydride hydrolases are a class of hydrolase enzymes that catalyze the hydrolysis of an acid anhydride bond. They are classified under EC number 3.6. One well known member of this class is GTPase GTPases are a large family of hydrolase e ...

, including

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 ...

s and

GTPase GTPases are a large family of hydrolase enzymes that bind to the nucleotide guanosine triphosphate (GTP) and hydrolyze it to guanosine diphosphate (GDP). The GTP binding and hydrolysis takes place in the highly conserved P-loop "G domain", a pro ...

) * EC 3.7 carbon-carbon bonds * EC 3.8

halide In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a flu ...

bonds * EC 3.9: phosphorus-nitrogen bonds * EC 3.10: sulphur-nitrogen bonds * EC 3.11: carbon-phosphorus bonds * EC 3.12: sulfur-sulfur bonds * EC 3.13: carbon-sulfur bonds

Clinical considerations

Hydrolase secreted by ''

Lactobacillus jensenii ''Lactobacillus jensenii'' is a normal inhabitant of the lower reproductive tract in healthy women. ''L. jensenii'' makes up 23% of vaginal microflora that is naturally occurring. It is also found on the skins of grapes at the time of their ha ...

'' in the human gut stimulates the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it i ...

to secrete bile salts that aids in the digestion of food.

Membrane-associated hydrolases

Many hydrolases, and especially

protease 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 ...

s associate with biological membranes as

peripheral membrane protein Peripheral membrane proteins, or extrinsic membrane proteins, are membrane proteins that adhere only temporarily to the biological membrane with which they are associated. These proteins attach to integral membrane proteins, or penetrate the perip ...

s or anchored through a single

transmembrane helix A transmembrane domain (TMD) is a membrane-spanning protein domain. TMDs generally adopt an alpha helix topological conformation, although some TMDs such as those in porins can adopt a different conformation. Because the interior of the lipid b ...

. Some others are multi-span

transmembrane proteins A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequentl ...

, for example

rhomboid protease The rhomboid proteases are a family of enzymes that exist in almost all species. They are proteases: they cut the polypeptide chain of other proteins. This proteolytic cleavage is irreversible in cells, and an important type of cellular regulation ...

Etymology and pronunciation

The word ''hydrolase'' () suffixes the

combining form Neoclassical compounds are compound words composed from combining forms (which act as affixes or stems) derived from classical Latin or ancient Greek roots. New Latin comprises many such words and is a substantial component of the technical an ...

of ''

-ase The suffix -ase is used in biochemistry to form names of enzymes. The most common way to name enzymes is to add this suffix onto the end of the substrate, ''e.g.'' an enzyme that breaks down peroxides may be called peroxidase; the enzyme that pro ...

'' to the ''hydrol'' syllables of ''

''.

References

EC 3 Introduction
from the Department of Chemistry at

Queen Mary, University of London , mottoeng = With united powers , established = 1785 – The London Hospital Medical College1843 – St Bartholomew's Hospital Medical College1882 – Westfield College1887 – East London College/Queen Mary College , type = Public researc ...