In biochemistry, a hydrolase is an enzyme that catalyzes the hydrolysis of a chemical bond. For example, an enzyme that catalyzed the following reaction is a hydrolase:
- A–B + H2O → A–OH + B–H
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.
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: