Inuence of chirality on the reactions in the active site of lyases Lyases are a class of enzymes that catalyze the breaking of various chemical bonds by molecular mechanisms that are different from the process of hydrolysis and oxidation, often forming a new double bond or a new ring structure. The common names of lyases are decarboxylase, dehydratase, or aldolase. The term synthase is used for the reverse reaction. The breaking of the adenosine triphosphate (ATP) into adenosine monophosphate (AMP) and pyrophosphate (PPi) is an example of a reaction carried out by the lyases. This reaction is an example that shows the feature that if a lyase requires one substrate in the forward direction of the reaction, then it requires two substrates in the reverse direction.