An allosteric effector can also act. negatively, inhibiting enzyme activity. Because allosteric regulators do not. bind to the same site on the protein. as the substrate, changing substrate. concentration generally does not. alter their effects. Of course there are other types of. regulation as well. Active site inhibitors: An inhibitory factor may bind to and block the active site. If this binding is reversible, then increasing the amount of substrate can over-come. the inhibition. An inhibitor of this type is known as a competitive inhibitor.