Hydrolase is a class of enzyme that is commonly used as biochemical catalysts that utilize water to break a chemical bond. This results in a division of a larger molecule to smaller molecules. Some common examples of hydrolase enzymes are esterases including lipases, phosphatases, glycosidases, peptidases, and nucleosidases. Esterases cleave ester bonds in lipids and phosphatases cleave phosphate groups off molecules. An example of crucial esterase is the acetylcholine esterase, which assists in transforming the neuron impulse into acetic acid after it the hydrolase breaks the acetylcholine into choline and acetic acid.^[1] Acetic acid is an important metabolite in the body, which becomes a nice intermediate for other reactions such as glycolysis. Lipases hydrolyze glycerides. Glycosidases cleave sugar molecules off carbohydrates and peptidases hydrolyze peptide bonds. Nucleosidases hydrolyze the bonds of nucleotides.^[2]

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. Fatty acids and other small molecules are used for synthesis and as a source of energy.^[1]

In biochemistry, a hydrolase is an enzyme that catalyzes the hydrolysis of a chemical bond. For example, an enzyme that catalyzes the following reaction is a hydrolase:

A–B + H₂O → A–OH + B–H

Nomenclature[edit]

Systematic names of hydrolases are formed as "substrate hydrolase." However, common names are typically in the form "substratease." For example, a nuclease is a hydrolase that cleaves nucleic acids.

Classification[edit]

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 bonds (esterases: nucleases, phosphodiesterases, lipase, phosphatase)


• 
  EC 3.2: sugars (DNA glycosylases, glycoside hydrolase)


• 
  EC 3.3: ether bonds


• 
  EC 3.4: peptide bonds (Proteases/peptidases)


• 
  EC 3.5: carbon-nitrogen bonds, other than peptide bonds


• 
  EC 3.6 acid anhydrides (acid anhydride hydrolases, including helicases and GTPase)


• 
  EC 3.7 carbon-carbon bonds
  


• 
  EC 3.8 halide 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[edit]

Hydrolase secreted by Lactobacillus jensenii in the human gut stimulates the liver to secrete bile salts that aids in the digestion of food.^[3]

Membrane-associated hydrolases[edit]

Many hydrolases, and especially proteases associate with biological membranes as peripheral membrane proteins or anchored through a single transmembrane helix.^[4] Some others are multi-span transmembrane proteins, for example rhomboid protease.

Etymology and pronunciation[edit]

The word hydrolase (/ˈhaɪdroʊleɪs, -leɪz/) suffixes the combining form of -ase to the hydrol syllables of hydrolysis.

See also[edit]

• Phosphorylase


• Serine hydrolase

References[edit]

• 
  EC 3 Introduction from the Department of Chemistry at Queen Mary, University of London, only covers 3.1-3.4


• More detailed taxonomy