Q.Describe the mechanism of enzyme action.

[!TLDR]

The question asks for a description of the mechanism by which an enzyme carries out its catalytic action. …

Enzyme action begins when the substrate binds to a specific pocket on the enzyme, the active site, forming a temporary enzyme-substrate (ES) complex: E + S -> ES. While held in this complex, the reaction is carried out, after which the product separates from the enzyme, releasing it to bind a fresh substrate molecule: ES -> E + P. The reason this speeds up the reaction is that forming the ES complex stabilises an intermediate, lower-energy transition state, which lowers the activation energy the reaction needs; without the enzyme, the same conversion would have to climb a much higher energy barrier and would therefore proceed far more slowly. …

• Describing only the ES-complex step and omitting the effect on activation energy, which is the actual reason the reaction speeds up. …