3.8.1.3. Kinetics of Reversible Un-Competitive Inhibition

• Uncompetitive inhibition, (anti-competitive inhibition), takes place when an enzyme inhibitor binds only to the complex formed between the enzyme and the substrate (the E-S complex).

3.8.1.3.1 Substrate Inhibition: A Special Case of Uncompetitive Inhibition

• A special case of uncompetitive inhibition is substrate inhibition which occurs at high substrate concentrations in about 20% of all known enzymes (e.g. invertase is inhibited by sucrose). It is primarily caused by more than one substrate molecule binding to an active site meant for just one, often by different parts of the substrate molecules binding to different subsites within the substrate binding site. If the resultant complex is inactive this type of inhibition causes a reduction in the rate of reaction, at high substrate concentrations.