Enzymes-rate of reaction

A chemical reaction proceeds when molecules with sufficient kinetic energy collide, break apart and recombine into a new chemical compound.

Initially product is formed at a higher rate, as shown by section A on the graph on the left, as there are plenty of substrate (reactant) molecules about. As substrate molecules become more scarce, the rate of product formation slows down, as shown in section B of the graph on the left.




As the temperature is increased, so is the average kinetic energy of the substrate molecules. The rate of product formation is also increased as more molecules have the energy required to undergo forceful collisions.
Introduction of an enzyme increases the rate of product formation and the end point is reached sooner.
Competitive inhibitors decrease the enzyme's ability to increase the rate of reaction. The inhibitor and the substrate compete for the active site. This inhibitor can be overcome to certain extent by increasing the concentration of substrate. In this way the substrate wins the race for the active site by overwhelming numbers.
Non-competitive, reversible inhibitors also slow the rate of product formation.
Allosteric inhibitors completely destroy the ability of the enzyme to catalyse the reaction by modifying the active site.