What is "lyase"

n. (context enzyme English) Any of many classes of enzyme that catalyze the breaking of a specific form of bond

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. The reverse reaction is also possible (called a " Michael addition”). For example, an enzyme that catalyzed this reaction would be a lyase:

Lyases differ from other enzymes in that they require only one substrate for the reaction in one direction, but two substrates for the reverse reaction.