What is the difference between competitive and non-competitive inhibition?

Competitive inhibition involves inhibitors binding to the active site, while non-competitive inhibition binds to an alternative site.

In competitive inhibition, the inhibitor and the substrate compete for the same active site on the enzyme. This means that the inhibitor closely resembles the substrate's structure, allowing it to fit into the active site and prevent the substrate from binding. As a result, the reaction rate decreases. However, this inhibition can be overcome by increasing the substrate concentration, which increases the chances of the substrate binding to the active site instead of the inhibitor.

On the other hand, non-competitive inhibition involves an inhibitor binding to an alternative site on the enzyme, known as the allosteric site. This binding causes a conformational change in the enzyme's structure, altering the shape of the active site and preventing the substrate from binding effectively. Unlike competitive inhibition, non-competitive inhibition cannot be overcome by simply increasing the substrate concentration, as the inhibitor does not compete with the substrate for the active site.

In summary, the key difference between competitive and non-competitive inhibition lies in the binding site of the inhibitor and the effect of substrate concentration on overcoming the inhibition. Competitive inhibitors bind to the active site and their effect can be reduced by increasing substrate concentration, while non-competitive inhibitors bind to an allosteric site, changing the enzyme's shape and their effect cannot be reduced by increasing substrate concentration.