Nature and Examples of Enzyme Catalysis

Enzymes are proteins that catalyze many reactions, particularly biochemical reactions, including many necessary for the maintenance of life. The catalytic action is usually very specific, and may be affected by the presence of other substances both as inhibitors and as coenzymes.1 

Enzymes are commonly grouped according to the type of reaction catalyzed. Six classes of enzymes have been identified  

L-tyrosine + 0, dihydroxyphenylalanine (L-DOPA) + H20 As a model reaction, we represent an enzyme-catalyzed reaction by 

2 A cofactor is a nonprotein compound that combines with an inactive enzyme to generate a complex that is catalytically active. Metal ions are common cofactors for enzymatic processes. A cofactor may be consumed in the reaction, but may be regenerated by a second reaction unrelated to the enzymatic process. 

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