Michealis Menten constants

This analysis can be applied to enzymatic as well as to simple chemical transformations [9-11], for uni- and multi-substrate [12] reactions according to Eqs. (1) and (2). denotes the product of Michealis-Menten constants for... 

This analysis can be applied to enzymatic as well as to simple chemical transformations [9-11], for uni- and multi-substrate [12] reactions according to Eqs. (1) and (2). nNKM denotes the product of Michealis-Menten constants for all substrates. In this analysis one assumes that kinetics follow the Michaelis-Menten model, which is the case for most antibody-catalyzed processes discussed below. The kcat denotes the rate constant for reaction of the antibody-substrate complex, Km its dissociation constant, and kuncat the rate constant for reaction in the medium without catalytic antibody or when the antibody is quantitatively inhibited by addition of its hapten. In several examples given below there is virtually no uncatalyzed reaction. This of course represents the best case. 

Affinity data, like substrate or receptor binding constants, rate constants, like association/dissociation, and Michealis Menten constants, inhibition constants, especially Kj and IC50 values of different enzymes, pharmacokinetic parameters, like absorption rate constants, distribution parameters, clearance, rate constants of metabolic degradation, and elimination rate constants,... 

Fig. 4. Analysis of the kinetic constants of the ferroxidase reaction catalyzed by soluble Fet3p. Fe(II) oxidation (A) and O2 consumption (B) were measured continuously and the residual substrate concentration was plotted with respect to time according to the integrated form of the Michealis-Menten equation as indicated in each panel. Fe(II) oxidation was followed by the appearance of Fe(III) at 315 nm while O2 consumption was determinedby the use of an O2 electrode. The [Fet3p] =0.2 fcM in 0.1 M MES buffer, pH 6.0, at 25°C. The curve in each panel is a linear least-squares fit of the data to...

Furthermore though the Michealis Menten scheme can be extended to cover more complex mechanisms with additional intermediates, the Km and kcai parameters now become even more complex combinations of individual rate and equilibrium constants. The kc t and Km parameters determined by these classical approaches are therefore not the fundamental constants defining the mechanism and significant effort is required to determine the true underlying equilibrium and microscopic rate constants. 

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