steady-state velocity

stead·y-state ve·loc·i·ty

the velocity of an enzyme-catalyzed reaction in which, over the time course of the study, the concentration of any enzyme species is constant (that is, for an enzyme-substrate binary complex, ES, d[ES]/dt ≈ 0; for this to hold true, the total enzyme concentration must be much less than the initial substrate concentration. Synonym(s): steady-state rate