[Determination of kinetic constants in the general case of cooperative type or Michaelis enzymes inhibited by their substrate: theoretic analysis].

For an enzyme (E) susceptible to substrate (S) inhibition, (S) can bind on one hand to (E) and on the other hand to (ES), leading to the dead-end complexes (SE) and (SES). In the general case where the (E)/(S) interaction obeys the Hill equation, the theoretical maximum velocity VM can be estimated when n not equal to 1, from the determination of velocities v beta at substrate concentrations S beta = Sm beta where Sm is the value corresponding to the actual maximum velocity vm. The Hill coefficient (n) as well as the constants KS, KSE and KSES corresponding to the respective dissociations of the complexes (ES), (SE) and (SES) are then determined from the equation: Ln (v/(VM-v] = nLnS-LnKS(1 + Sn/KSE + S2n/KS KSES) and its two asymptotes.