Classes of Enzymes

Class

Chemical Reaction Catalyzed

Sample Enzymes

Oxidoreductase

Oxidation-reduction in which oxygen and hydrogen are gained or lost

Cytochrome oxidase, lactate dehydrogenase

Transferase

Transfer of functional groups, such as an amino group, acetyl group, or phosphate group

Acetate kinase, alanine deaminase

Hydrolase

Hydrolysis (addition of water)

Lipase, sucrase

Lyase

Removal of groups of atoms without hydrolysis

Oxalate decarboxylase, isocitrate lyase

Isomerase

Rearrangement of atoms within a molecule

Glucose-phosphate isomerase, alanine racemase

Ligase

Joining of two molecules (using energy usually derived from the breakdown of ATP)

Acetyl-CoA synthetase, DNA ligase

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