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Michaelis–Menten kinetics

The dependence of an initial rate of reaction upon the concentration of a substrate S that is present in large excess over the concentration of an enzyme or other catalyst (or reagent) E with the appearance of saturation behaviour following the Michaelis-Menten equation:
v = V S K m + S,
where v is the observed initial rate, V is its limiting value at substrate saturation (i.e. S ≫ K m), and K m the substrate concentration when v = V 2. The definition is experimental, i.e. it applies to any reaction that follows an equation of this general form. The symbols V max or v max are sometimes used for V. The parameters V and K m (the 'Michaelis constant') of the equation can be evaluated from the slope and intercept of a linear plot of v −1vs. S −1 (a 'Lineweaver–Burk plot') or from slope and intercept of a linear plot of vvs. v S ('Eadie–Hofstee plot'). A Michaelis–Menten equation is also applicable to the condition where E is present in large excess, in which case the concentration E appears in the equation instead of S. The term has sometimes been used to describe reactions that proceed according to the scheme:
E + S ⇄ k −1 k 1 ES → k cat Products
in which case K m = k −1 + k cat k 1 (Briggs–Haldane conditions). It has more usually been applied only to the special case in which k −1 ≫ k cat and K m = k −1 k 1 = K s; in this case K m is a true dissociation constant (Michaelis–Menten conditions).
PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1140
PAC, 1996, 68, 149 (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 172
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IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
Last update: 2014-02-24; version: 2.3.3.
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