What is the process called when the binding of a substrate to one active site enhances the function of all active sites in a multisubunit enzyme?

The process referred to in the question is known as cooperativity. This phenomenon occurs in multisubunit enzymes, where the binding of a substrate to one active site influences the activity of other active sites within the enzyme. When a substrate binds to one subunit, it can induce a conformational change that makes it easier for additional substrate molecules to bind to other active sites. This can lead to a marked increase in the overall activity of the enzyme.

Cooperativity is a crucial aspect of enzyme regulation, allowing for greater responsiveness to changes in substrate concentration. It contrasts with non-cooperative enzymes, where the binding of a substrate to one site doesn’t affect others. This feature is particularly important in processes where cells need to finely tune their metabolic responses based on substrate availability.