Fig. 1.

Schematic showing slow-tight inhibitor (I) binding to enzyme (E). This is a two-step process with the fast formation of a less stable intermediate complex (E-I) defined by k3 and k4, followed by the formation of a more stable but still reversible complex (E-I∗) defined by k5 and k6. When k6 approaches zero, the complex is essentially irreversible.