Fig. 5
Kinetics predictions for multisite protein species with marginally different association constants. The kinetics of multisite protein species was investigated for the intermediate (N 1/L T , N 2/L T and N 3/L T in a as well as the apo- and fully bound conformations (N 0/L T and N 4/L T respectively in b in response to step change of ligand from U 0/K = 0.001 to U 1/K = 1.43 for marginally different association constants h 1 = 1, h 2 = 0.9, h 3 = 0.8, h 4 = 0.7 and the same dissociation constants h −1  = h −2  = h −3  = h −4  = 1. Similar analysis was also performed when step change was U 0/K = 0.001, U 1/K = 100 for apo- (c) and fully bound (d) forms. The calculations show that the final level of the multisite protein species are defined by the ligand concentration after the step change. It is very clear that the fully bound species are not saturated and most of the ligand is distributed among species bound to fewer ligands. However, step change application of ligand with much higher concentration from U 0/K = 0.001 to U 1/K = 100 for apo- (c) and fully bound (d) species demonstrate that the application of higher concentrations of ligand causes fully saturates the protein