FIG. 4.

Kinetic schemes for a substrate-induced inactivation mechanism. (A) General scheme; (B) simplified scheme. E, native enzyme; E′, inactive or poorly active form of the enzyme induced by the substrate; S, substrate; P, product. E·S and E′·S represent substrate-enzyme complexes. K₁ to K₄ represent dissociation constants corresponding to the different equilibria. k_p and k′_p represent the rate constants characterizing the hydrolytic decay of E·S and E′·S, respectively. The kinetic scheme shown in panel A can be simplified to the scheme shown in panel B when the conversion of E′ into E is fast and the equilibrium E ↔ E′ is completely displaced toward E.