申論題

7. (15%) Enzymes serve as catalysts in many chemical reactions in living systems. The simplest such reactions transform a single substrate into a product with the help of an enzyme, which may be represented schematically as

In this mechanism, the enzyme E is a catalyst, which only facilitates the reaction, so that its total concentration, free plus combined, [E] + [ES] = [E]o is a constant.

(a) (3%) Write down a system of rate equations for the change of concentrations of these four chemical species with time t by applying the law of mass action (the rate of a reaction is proportional to the product ofthe concentrations of the reactants).