Time-dependent closed form solutions for fully competitive enzyme reactions

An analytic formalism developed earlier to describe the time evolution of t he basic enzyme reaction is extended to fully competitive systems. Time-dep endent closed form solutions are derived for the three nominal cases of com petition: even, slow and fast inhibitors, allowing for the first time the c omplete characterization of the reactions. In agreement with previous work, the time-independent Michaelis-Menten approach is shown to be inaccurate w hen a fast inhibitor is present. The validity of the quasi-steady-state app roximation on which the present framework is based is also revised. (C) 200 0 Society for Mathematical Biology.