Statistical considerations in the estimation of enzyme kinetic parameters by the direct linear plot and other methods

Abstract

The statistical implications of the direct linear plot for enzyme kinetic data, described in the preceding paper (Eisenthal & Cornish-Bowden, 1974), are discussed for the case of the Michaelis–Menten equation. The plot is shown to lead directly to non-parametric confidence limits for the kinetic parameters, V and Km, which depend on far less sweeping assumptions about the nature of experimental error than those implicit in the method of least squares. Median estimates of V and Km can also be defined, which are shown to be more robust than the least-squares estimates in a wide variety of experimental situations.