The kinetic properties of the wild-type and Tyr57Trp mutant form of human muscle FBPase.

The dissociation constant of the enzyme-substrate complex (Ks), the inhibition constant of FBPase by its substrate (Kis) and β values were calculated assuming the model of partial noncompetitive inhibition by substrate [18].The Hill equation was used to calculate dissociation constants for Mg2+, Ca2+ and AMP.Ki is a dissociation (inhibitory) constant for AMP or Ca2+, Ka is a dissociation (activatory) constant for Mg2+ and n is the Hill constant.The mean values and respective standard error calculated from 3 independent experiments are presented in the Table.