Evaluation of thermodynamic consistency of kinetic parameters in cyclic enzyme-catalyzed reaction networks

It is shown by analysis of a cyclic enzymatic network that the presence zero net flux/current cycles impose strong thermodynamic constraints on values kinetic parameters. Thermodynamic carried out for four-node pyramidal reaction involving conversion 7,8-­dihydrofolate (H2F) and NADPH in H+ to 5,6,7,8-­tetrahydrofolate (H4F) NADP+ catalyzed universal enzyme dihydrofolate reductase (DHFR). The complete set empty routes DHFR pathway identified, equations imposed rate constants various elementary steps are written down, consistency experimentally determined evaluated. visual approach based theory graphs can be employed test parameters general enzyme-catalyzed networks.