Question

Match the co-factor given in list I with the enzyme given in list II.

Choose the correct answer from the options given below:

• A. (A)-(II), (B)-(III), (C)-(IV), (D)-(I)
• B. (A)-(I), (B)-(III), (C)-(II), (D)-(IV)
• C. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
• D. (A)-(III), (B)-(IV), (C)-(I), (D)-(II)

Hint:

Remember these classic metalloenzyme pairings:
- Carbonic anhydrase \(\rightarrow \text{Zn}^{2+}\)
- Hexokinase Kinases \(\rightarrow \text{Mg}^{2+}\)
- Glutathione peroxidase \(\rightarrow \text{Se}\)

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Many enzymes require non-protein metal ions or trace elements (co-factors) to stabilize their structure or participate directly in catalysis.

Step 2: Detailed Explanation:
- Copper (\(\text{Cu}^{2+}\)): Is a co-factor in Cytochrome Oxidase (A \(\rightarrow\) III), where it participates in electron transfer during the final step of the respiratory electron transport chain.
- Zinc (\(\text{Zn}^{2+}\)): Is essential for the catalytic activity of Carbonic anhydrase (B \(\rightarrow\) IV), helping coordinate water molecules at the active site.
- Magnesium (\(\text{Mg}^{2+}\)): Co-ordinates with the phosphate groups of ATP to stabilize the substrate in phosphotransfer reactions catalyzed by kinases like Hexokinase (C \(\rightarrow\) I).
- Selenium (\(\text{Se}\)): Is present as selenocysteine in the active site of Glutathione peroxidase (D \(\rightarrow\) II), an enzyme that neutralizes peroxides.

Step 3: Final Answer:
The correct matching sequence is (A)-(III), (B)-(IV), (C)-(I), (D)-(II).