The tight-binding variant of the integrated rate Eqn (4) (shown as Eqn 6.2 in Copeland and elsewhere in the biochemical literature) applies only to the one-step Mechanism A. Specifically, Eqn (4) does not apply to the two-step inhibition Mechanism B. Therefore, no attempts should be made to interpret k obs values derived from Eqn (4) by using the classical (as opposed to tightbinding) mechanism-selection formulas.