The measurement of true initial rates is not always absolutely necessary to estimate enzyme kinetic parameters.

ABSTRACT: In the chapters dealing with enzyme reactions, the authors of all Biochemistry textbooks and of even more specialized texts consider that the characteristic parameters (k_cat and K_m) must be determined under initial or steady-state rate conditions. This implies the transformation of a very limited proportion of substrate (at most 10-20%) or a continuous recording of the product or substrate concentration vs. time. Both options can present practical difficulties. Is it possible to get around these very stringent conditions? Here we show that in the most favourable cases up  to 70% of the substrate can be converted resulting in systematic errors on the parameters (that can easily be taken account of) if the simple Henri-Michaelis-Menten equation is utilised. Alternativel

SUBMITTER: Frere JM 

PROVIDER: S-EPMC10497622 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature