ABSTRACT
Michaelis-Menten constant, the identity of which
is Km ¼ k-1/k1 for the case of rapid equilibrium, or Km ¼ (k-1þk2)/k1 for the case of quasi-steady state. A graphical representation of Michaelis-Menten kinetics is
shown in Fig. 1. The conversion rate of the enzyme-sub-
strate intermediate into enzyme and product is governed by
the turnover number (kcat). When the reaction mechanism
is that of Michaelis-Menten, and all the reaction steps are
fast, kcat is simply a first-order rate constant, and describes
the maximum amount of substrate that can be converted
to product per time (kcat¼Vmax/[E]). The specificity constant (kcat/Km) is an apparent second order rate constant
that describes the specificity of the enzyme for the
substrate.
