Enzymes are complex nitrogenous organic compounds which are produced by Living plants and animals. They are protein molecules of higher molecular masses. They are effective catalysts termed as “biochemical catalysts”

Mechanism of enzyme catalysis- Their are number of cavities present on the surface of colloidal particle of enzymes. They have specific shape and contains group like –COOH ,-SH, -OH. etc. they are active centres of enzyme particle molecules of reactant which have complimentary shape fit into this cavities, this formes activated complex Which then decompose to yield products. This reaction occur in 2 steps-

_{1) Enzyme(E) + Substrate (S)} → _ES

2) ES → Enzyme + Products