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

Competitive inhibition occurs when a molecule similar in shape to the substrate binds to the active site of the enzyme, preventing the substrate from binding. Non-competitive inhibition occurs when a molecule binds to a site on the enzyme other than the active site, causing a change in the enzyme's shape and preventing the substrate from binding.

In competitive inhibition, the inhibitor competes with the substrate for binding to the active site of the enzyme. The inhibitor may be structurally similar to the substrate or may be a completely different molecule. The degree of inhibition depends on the concentration of the inhibitor and the affinity of the inhibitor for the enzyme. Competitive inhibition can be overcome by increasing the concentration of the substrate.

In non-competitive inhibition, the inhibitor binds to a site on the enzyme other than the active site, causing a change in the enzyme's shape. This change may prevent the substrate from binding to the active site or may make it more difficult for the enzyme to catalyse the reaction. Non-competitive inhibition cannot be overcome by increasing the concentration of the substrate.

Both competitive and non-competitive inhibition can be reversible or irreversible. Reversible inhibition occurs when the inhibitor can be removed from the enzyme, allowing the enzyme to function normally. Irreversible inhibition occurs when the inhibitor permanently binds to the enzyme, rendering it inactive.