A chemical equilibrium is a state at which the rate of forward reaction is equal to the rate of backward reaction. When an enzyme catalyzed reaction is at equilibrium there is no net there is no net change in the amount of reactants or products. Enzymes do not affect the rate of equilibrium but the speed up the attaining of equilibrium by a reaction. Therefore, at equilibrium of a reversible enzyme catalyzed chemical reaction the amount of reactants and products present is constant.