Which statement is true about mixed inhibitors?

Mixed inhibitors have a unique mechanism of action that allows them to bind to both the free enzyme (E) and the enzyme-substrate complex (ES), which makes them different from other types of enzyme inhibitors. The binding of a mixed inhibitor can occur at two distinct sites: one on the free enzyme and another on the enzyme-substrate complex.

This dual binding capability influences both the affinity of the enzyme for its substrate (Km) and the maximum velocity of the reaction (Vmax). When a mixed inhibitor binds to the free enzyme, it can increase Km due to decreased binding affinity, while binding to the enzyme-substrate complex can potentially decrease Vmax since the inhibitor interferes with the catalytic activity.

The correct statement reflects the versatility of mixed inhibitors, as they can bind to either form of the enzyme, leading to the alterations in reaction kinetics observed with this type of inhibition. Other statements do not accurately portray the behavior and effects of mixed inhibitors, making this understanding crucial in characterizing their pharmacological implications.