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:

$Math - e$ ,

where $Math - symbol$ is the observed initial rate, $Math - symbol$ is its limiting value at substrate saturation (i.e. $Math - ei$ ), and $Math - symbol$ the substrate concentration when $Math - ei$ . The definition is experimental, i.e. it applies to any reaction that follows an equation of this general form. The symbols $Math - symbol$ or $Math - symbol$ are sometimes used for $Math - symbol$ . The parameters $Math - symbol$ and $Math - symbol$ (the 'Michaelis constant') of the equation can be evaluated from the slope and intercept of a linear plot of $Math - ei$ vs. $Math - ei$ (a 'Lineweaver–Burk plot') or from slope and intercept of a linear plot of $Math - ei$ vs. $Math - ei$ ('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 $Math - text$ appears in the equation instead of $Math - text$ . The term has sometimes been used to describe reactions that proceed according to the scheme:

$Math - c$

in which case $Math - ei$ (Briggs–Haldane conditions). It has more usually been applied only to the special case in which $Math - ei$ and $Math - ei$ ; in this case $Math - symbol$ is a true dissociation constant (Michaelis–Menten conditions).