A Comparison of Estimates of Michaelis-Menten Kinetic Constants from Various Linear Transformations

The parameters which characterize this equation, and which must ordinarily be estimated from the observed data, are ‘v,,,, the maximum initial velocity which is theoretically attained when the enzyme has been “saturated” by an infinite concentration of substrate, and K,, the Michaelis constant which is numerically equal to the concentration of substrate for half-maximal initial velocity. Since the relationship between the independent variable, Cs, and the dependent variable, v, is curvilinear, it has long been customary to facilitate estimation of the two parameters by plotting the experimental data according to one of the following three linear transformations of Equation 1. v = Vmax - K&/C’s) (la) (Cs/v) = (Km/Vm,x) + (l/Vm,x)Cs (lb)