PMDC Verified Question 15 of 47
The inhibition in which or inhibitor does not combine directly with the enzyme but binds to the enzyme substrate complex is called:
A
Reversible inhibition
B
Competitive inhibition
C
Uncompetitive inhibition
D
Non-competitive inhibition
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: Uncompetitive inhibition
Concept:

In enzyme kinetics, inhibitors can bind to the free enzyme, the enzyme-substrate (ES) complex, or both. The specific binding target defines the kinetic pattern.

Formula:

$$ \text{E} + \text{S} \rightleftharpoons \text{ES} \xrightarrow{\text{+ I}} \text{ESI (inactive)} $$

Solution:

  • If an inhibitor exclusively binds to the Enzyme-Substrate (ES) complex (and has zero affinity for the free enzyme), it locks the substrate inside and prevents product formation.
  • This specific mechanism is defined as uncompetitive inhibition.


Why other options are incorrect:

Competitive inhibitors bind only to the free enzyme. Non-competitive inhibitors can bind to both the free enzyme AND the ES complex equally. Reversible inhibition is a broad category that includes all of these.

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