Biology Enzymes UHS 2022
PMDC Verified Question 43 of 79
Zinc ion is attached to the active site of the enzyme carboxypeptidase. The zinc ion functions as:
A
An inhibitor molecule
B
A coenzyme molecule
C
An activator
D
Controller of allosteric site
Tap any option to test your recall and reveal the step-by-step Propolis autopsy.

Propolis Cognitive Error Autopsy

Official Correct Choice:
Option C: An activator
Concept:

Many enzymes require non-protein helper molecules for their catalytic activity. When this helper is an inorganic metal ion, it has a specific designation.

Solution:

  • A detachable inorganic co-factor is known as an activator.
  • Metal ions like \( \text{Zn}^{2+} \), \( \text{Mg}^{2+} \), and \( \text{Fe}^{2+} \) often act as activators by temporarily binding to the enzyme and helping to draw electrons away from the substrate, facilitating the reaction.


Why other options are incorrect:

Coenzymes are organic molecules (like vitamins). Inhibitors decrease enzyme activity, whereas zinc is required for carboxypeptidase to function. It binds to the active site to aid catalysis, not an allosteric regulatory site.

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