Enzyme Inhibition

ENZYME INHIBITION


ENZYME INHIBITION

  • Enzyme inhibitor binds with enzyme and decreases a catalytic activity.

Types of Enzyme Inhibition-

  1. Reversible
  2. Irreversible
  3. Allosteric
  4. Reversible Inhibition– binds through non-covalent bonds and activity of enzyme is restored. Divided into-

a) Competitive inhibitorKm 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.

Exam Important

  1. Reversible Inhibition- binds through non-covalent bonds and activity of enzyme is restored.
  2. Competitive inhibitor- Km increased, Vmax unchanged.
  3. Competitive inhibitor- Succinate dehydrogenase by melanate.
  4. Non competitive inhibitor- Km unchanged, Vmax decrease, mostly irreversible.
  5. Non competitive inhibitor- E.g.- Cyanide by Cytochrome C Oxidase.
  6. Suicidal Inhibitor- Allopurinol inhibit Xanthine oxidase.
Type of inhibitor Km Vmax
Reversible inhibbitor Increased No effect
Competitive No effect Decreased
Non-competitive Decreased Decreased
Uncompititive No effect Decreased
Irrversible inhibitor (same as reversible Increased No effect
Don’t Forget to Solve all the previous Year Question asked on ENZYME INHIBITION

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