Relevance of Enzyme Mechanism

The postulation of a model of the mechanism of an enzyme reaction encompasses consideration of the elementary steps. In an enzyme reaction, there are always several steps which make up a mechanism, including at least one binding step and a catalytic one. The Michaelis-Menten equation [Eq. (9.1)] discussed in Chapters 2 and 5 is the kinetic manifestation of a simple mechanism encompassing binding and reaction  

Included in these methods are (i) determination of product distribution, (ii) steady-state kinetics, (iii) non-stationary methods for the trapping of intermediates, (iv) determination of the influence of Briansted and Hammett effects, (v) kinetic isotope effects, and finally (vi) use of transition-state analogs. 

The general equation relating the product ratio at infinite time, P, to the rate constants (kt, k 3 = rates of equilibration of conformers X and Y, k2 = rate of formation of product A from X, k3 = rate of formation of B from Y) for the conformation-ally mobile system described by Eq. (9.2) is given by Eq. (9.3), with K=k1/k 1 (Zefirov, 1977). 

As a consequence of the Curtin-Hammett principle, one of the most useful means of investigating a mechanism is (not altogether unexpectedly) to measure the distribution of product(s). One prerequisite for measuring product distribution is a proper assay. 

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