Answer:
The uncompetitive and mixed inhibitors are not affected by the substrate concentration while inhibition by a competitive inhibitor can be overcome by increasing the concentration of the substrate.
Explanation:
A competitive inhibitor competes with the substrate for the active site of the enzyme. When the competitive inhibitor combines with the enzyme and forms the enzyme-inhibitor complex (EI complex), the substrate cannot bind to the active site. However, the inhibition by competitive inhibitor can be overcome by increasing the substrate concentration around the enzyme which in turn would allow the substrate to bind to the active site and the reaction would proceed.
On the other hand, an uncompetitive inhibitor binds to the site at the enzyme different from the active site. Once the ES complex is formed, the uncompetitive inhibitor joins the complex to inhibit the enzymatic activity.
Likewise, a mixed inhibitor also occupies a site on the enzyme distinct from the active site for the substrate. A mixed inhibitor binds to the enzyme or ES complex to inhibit the reaction.
Since the binding site for uncompetitive and mixed inhibitors are distinct from the substrate-binding site on the enzyme, increasing the substrate concentration can not overcome the inhibition.
