Question

(a) How is mature insulin different from proinsulin secreted by pancreas in humans? (b) Explain how was human functional insulin produced using rDNA technology (C) Why is ,the functional insulin produced considered better than the ones used earlier by diabetic patients?

Answer 1

1. Proinsulin contains an extra stretch called c peptide. This c peptide is not present in the mature insulin and is removed during maturation into insulin.This is the major difference between them.
2. Firstly we prepare two DNA sequences corresponding to chain A and B of human insulin. It is introduced in plasmid of Escherichia coli to produce insulin chains .Chain A and B are produced separately, extracted and combined by creating disulphide bonds to form human insulin or humulin.
3. The functional insulin produced considered better than the ones used earlier by diabetic patients because
   

• It is less expensive.
• It causes fewer allergic reactions.
• It is more rapidly absorbed and shows it's effectiveness over a short period of time.
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