Inhibitors Of Enzymes

Substances that can reduce the catalytic activity of the enzyme without causing denaturation of the enzyme protein are collectively referred to as inhibitors of the enzyme [5]. Most inhibitors bind to the necessary groups inside and outside the enzyme activity center, thereby inhibiting the catalytic activity of the enzyme. The enzyme activity was recovered after the inhibitor was removed. The inhibition of enzyme can be divided into irreversible inhibition and reversible inhibition according to the degree of tight combination of inhibitor and enzyme.

1. Irreversible inhibitors are mainly covalently bound to enzymes

Inhibitors of irreversible inhibition usually combine with the necessary groups on the active center of the enzyme by covalent bonds to inactivate the enzyme. This inhibitor cannot be removed by dialysis, ultrafiltration and other methods.

2. Noncovalent binding of reversible inhibitors to enzymes and/or enzyme substrate complexes

Reversible inhibition inhibitors can reversibly bind to the enzyme and/or enzyme substrate complex through non covalent bonds to reduce or eliminate the enzyme activity. The inhibitor can be removed by dialysis or ultrafiltration. Here are three common reversible inhibitory effects.

1) Competitive inhibition

The structure of the inhibitor is similar to that of the substrate, which can compete with the substrate for the active center of the enzyme, thus preventing the enzyme from combining with the substrate to form intermediate products.

2) Non competitive inhibition

Some inhibitors combine with essential groups outside the active center of the enzyme, which does not affect the combination of the enzyme and the substrate. There is no competition between substrate and inhibitor. However, the enzyme substrate inhibitor complex (ESI) cannot further release the product [6].

3) Anticompetitive inhibition

Such inhibitors only bind to the intermediate products (ES) formed by enzymes and substrates, resulting in the decrease of the amount of intermediate products. In this way, the amount of products converted from intermediates is reduced, and the amount of dissociated enzymes and substrates from intermediates is also reduced