Which peptide chain is removed during maturation of proinsulin

Options

A. D chain
B. C chain
C. B Chain
D. A chain

Answer

To answer the question "Which peptide chain is removed during maturation of proinsulin?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Proinsulin Structure**:
- Proinsulin is a precursor molecule that consists of three peptide chains: A chain, B chain, and C chain.
- The A chain and B chain are connected by disulfide bonds.

2. **Maturation Process**:
- During the maturation of proinsulin into insulin, the C chain (also known as the C-peptide) is removed.
- The A and B chains remain linked together through disulfide bonds to form the active insulin molecule.

3. **Role of Enzymes**:
- The cleavage of the C-peptide from proinsulin is facilitated by enzymes known as peptidases.

4. **Final Structure of Insulin**:
- After the removal of the C-peptide, the remaining structure consists of only the A and B chains, which together form the functional insulin.

5. **Conclusion**:
- Therefore, the peptide chain that is removed during the maturation of proinsulin is the C chain.

### Final Answer:
The peptide chain that is removed during maturation of proinsulin is the **C-chain**.

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