EXPLICIT EXPRESSIONS FOR MICHAELIS-MENTEN KINETIC PARAMETERS FROM THE DIRECT LINEAR PLOT

A least square estimation of the Michaelis-Menten kinetic parameters from the direct linear plot was obtained using a minimization procedure developed to produce explicit expressions for K_m and V_max, as a function of substrate concentration and measured reaction rate. This was accomplished by minimizing the distance between a point in parameter space representing the optimal parameter values and all the lines obtained from the direct linear plot. Under certain limiting conditions, the developed generalized expressions simplify to the least square estimates of Eadie-Hofstee and inverse Hanes plots. The expressions developed are simple to use and can accommodate replicate data, producing less conservative error bounds for the parameters than those obtained by other techniques.