Final answer:
Non-competitive inhibition affects enzymes by binding to an allosteric site, changing the enzyme's shape, and decreasing the enzyme's affinity for the substrate, which impacts the maximal rate of the reaction irrespective of substrate concentration.
Step-by-step explanation:
What is unique about non-competitive inhibition? Non-competitive inhibition is a form of enzyme inhibition where the non-competitive inhibitor binds to an allosteric site rather than the active site of the enzyme. This binding results in a conformational change in the enzyme, altering the shape of the active site and subsequently decreasing the enzyme's affinity for its substrate. Unlike competitive inhibition, non-competitive inhibition does not depend on the concentration of the substrate, because adding more substrate does not reverse the inhibition.
This is because the inhibitor can bind to the enzyme whether or not the substrate is already bound, and it affects the maximal rate of the reaction without impacting the initial rate.
Furthermore, since non-competitive inhibitors bind to sites other than the active site, they do not directly compete with the substrate, which means that their action is unaffected by the concentration of the substrate. This distinct mechanism is relevant in regulatory processes and in the design of certain pharmaceuticals, as it offers a way to control enzyme activity through a pathway other than substrate concentration.