The reliability of Michaelis constants and maximum velocities estimated by using the integrated Michaelis–Menten equation

Abstract

1. Experimental progress curves were simulated for a reaction obeying Michaelis–Menten kinetics. 2. K_m and V were estimated (a) by fitting the integrated Michaelis–Menten equation to the progress curves, and (b) from the initial slopes of the curves (i.e. from initial velocities). 3. The integrated equation could not be fitted successfully by a non-linear method, so it was transformed and fitted by a linear method. 4. Provided that the initial substrate concentration was greater than K_m and the data were precise enough, the integrated equation gave parameter estimates which were unbiased and as reliable as those derived from initial velocities although based on fewer experiments. 5. The integrated equation could be used for progress curves of unknown origin.