The step that proved to be the main challenging obstacle in the production of human insulin by genetic engineering is :

Options

A. Removal of C-peptide from active insulin
B. Getting insulin assembled into a mature form
C. Addition of C-peptide to proinsulin
D. Splitting A and B polypeptide chains

Answer

To solve the question regarding the main challenging obstacle in the production of human insulin by genetic engineering, we can break down the process into several steps:

### Step-by-Step Solution:

1. **Understanding the Source of Insulin**:
- Human insulin is produced from the genetic material (DNA) obtained from the human pancreas. This DNA contains the instructions for making insulin.

**Hint**: Identify the source of insulin and its genetic material.

2. **Recombination with Bacterial DNA**:
- The human insulin gene is inserted into bacterial DNA (plasmid) through a process called recombination. This allows bacteria to produce human insulin.

**Hint**: Consider how human genes can be integrated into bacterial systems.

3. **Extraction of Insulin DNA**:
- After successful recombination, the next step involves extracting the insulin DNA from the bacteria. This step is crucial for the production of insulin.

**Hint**: Think about the importance of isolating the desired DNA after recombination.

4. **Maturation of Pro-insulin**:
- The insulin produced initially is in the form of pro-insulin, which contains a segment known as C-peptide. For insulin to be active, it must be converted from pro-insulin to its mature form, which involves removing the C-peptide.

**Hint**: Focus on the transformation from pro-insulin to active insulin and the role of C-peptide.

5. **Challenge of C-peptide Removal**:
- The main obstacle in this process is the removal of the C-peptide from pro-insulin to form mature insulin. This step is complex and critical because if C-peptide remains, it can lead to incorrect insulin formation.

**Hint**: Identify which step poses the greatest difficulty in the production process.

6. **Conclusion**:
- The main challenging obstacle in the production of human insulin by genetic engineering is the **removal of C-peptide from pro-insulin to obtain mature insulin**.

### Final Answer:
The step that proved to be the main challenging obstacle in the production of human insulin by genetic engineering is **getting insulin assembled into a mature form** (removal of C-peptide).

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