The Specific Velocity Plot

Abstract

A new method is described for plotting kinetic results for inhibited enzymatic reactions. The plot is particularly designed for the analysis of hyperbolic, mixed‐type inhibitors, but can be applied to any other linear system. The method consists of plotting experimental data in a normalized way, as v₀/v_i versus the specific velocity σ/(1 +σ), where v₀/v_i represents the ratio of the initial velocities for the non‐inhibited and inhibited reactions at a given substrate concentration [S], and σ is the [S]/K_m ratio. The procedure provides a simple way of determining the inhibition constatnts K_i and K^′_i, i.e. the dissociation constants of the EI and ESI complexes, respectively, and the velocity saturation values.