- Enzyme inhibitor binds with enzyme and decreases a catalytic activity.
Types of Enzyme Inhibition-
- Reversible Inhibition– binds through non-covalent bonds and activity of enzyme is restored. Divided into-
a) Competitive inhibitor– Km increased, Vmax unchanged.
- E.g.- Succinate dehydrogenase by melanate.
b) Non competitive inhibitor- Km unchanged, Vmax decrease, mostly irreversible.
- E.g.- Cyanide by Cytochrome C Oxidase.
- Carbonic anhydrase by Acetazolamide
2. Irreversible Inhibition– binds covalently with an enzyme.
a) Suicidal Inhibitor– irreversible binding to enzyme and inhibit enzyme.
- E.g. Allopurinol inhibit Xanthine oxidase, cyclooxygenase.
3. Feedback Inhibition- called as end product inhibition.
- E.g. AMP inhibits first step in purine synthesis.
- Reversible Inhibition- binds through non-covalent bonds and activity of enzyme is restored.
- Competitive inhibitor- Km increased, Vmax unchanged.
- Competitive inhibitor- Succinate dehydrogenase by melanate.
- Non competitive inhibitor- Km unchanged, Vmax decrease, mostly irreversible.
- Non competitive inhibitor- E.g.- Cyanide by Cytochrome C Oxidase.
- Suicidal Inhibitor- Allopurinol inhibit Xanthine oxidase.
|Type of inhibitor||Km||Vmax|
|Reversible inhibbitor||Increased||No effect|
|Irrversible inhibitor (same as reversible||Increased||No effect|