What is the main challenge for production of insulin using r-DNA techniques

Answer

### Step-by-Step Solution:

1. **Understanding Insulin Structure**: Insulin is initially produced in an immature form that consists of three chains: the A chain, the B chain, and the C chain. The C chain is later removed during the maturation process, leaving only the A and B chains in the mature form of insulin.

2. **Recombinant DNA Technology (rDNA)**: rDNA technology involves the manipulation of DNA to produce specific proteins. In the case of insulin, this technology allows for the production of insulin by inserting the human insulin gene into bacteria or yeast.

3. **Production of Insulin**: The first artificial insulin was produced by the Eli Lilly company using rDNA technology. They synthesized the A and B chains of insulin separately.

4. **Main Challenge**: The primary challenge in producing insulin using rDNA techniques is the assembly of the A and B chains into a functional insulin molecule. After synthesizing these chains, they must be correctly linked together.

5. **Disulfide Bonds**: The A and B chains are connected through disulfide bonds. The process of forming these bonds and ensuring that the chains are properly assembled is the main hurdle in the production of insulin.

6. **Conclusion**: Therefore, the main challenge for the production of insulin using rDNA techniques is the assembly of the A and B chains into a mature insulin molecule.