Final answer:
An allosteric inhibitor d) binds to an enzyme at an allosteric site, which is different from the active site, leading to a conformational change that decreases the enzyme's affinity for the substrate and reduces or prevents its activity.
Step-by-step explanation:
An allosteric inhibitor is a molecule that binds to an enzyme at a site other than the enzyme's active site. This binding causes a conformational change in the enzyme, which in turn alters the shape of the active site and decreases its affinity for the substrate.
Consequently, the activity of the enzyme is reduced or prevented because the substrate can no longer bind effectively to the active site. Unlike competitive inhibitors that bind directly to the active site, allosteric inhibitors bind to the allosteric site, inducing a change in enzyme shape that affects the active site indirectly.
It's important to note that the impact of allosteric inhibitors is distinct from that of allosteric activators. While allosteric activators increase the enzyme's affinity for its substrate, leading to enhanced enzyme activity, allosteric inhibitors decrease affinity, thereby inhibiting the enzyme's function.