Extending the Quasi - Steady Approximation by Changing

The classical Michaelis-Menten approximation for scheme (la) is the archetypal example for the use of the quasi-steady state (QSS) approximation. This approximation is a major simplifying step throughout biology, with its enormous range of time scales, and indeed in many other branches of science. The quasi-steady state assumption (QSSA) often yields revealing analytic formulas and it frequently circumvents problems of stiffness in the numerical integration of systems of differential equations. It is thus of