At high substrate concentrations, what happens to the active sites of enzymes?

At high substrate concentrations, the active sites of enzymes become fully saturated. This means that the enzyme molecules have bound as much substrate as they can handle, and all the active sites are occupied. In this state, adding more substrate will not increase the rate of the reaction because the enzyme is working at its maximum capacity, which is known as Vmax.

This saturation occurs because there is a finite number of active sites available on each enzyme molecule. Once every enzyme has its active site occupied by a substrate molecule, the reaction reaches a point where the additional substrate cannot further affect the rate of product formation, as there are no available active sites to accommodate it.

Understanding saturation is crucial in biochemistry as it highlights the relationship between enzyme activity and substrate concentration, reflecting the dynamics involved in enzyme kinetics, such as those described by the Michaelis-Menten model.