Question

With regard to insulin choose correct options. 
(a) C-peptide is not present in mature insulin. 
(b) The insulin produced by rDNA technology has C-peptide. 
(c) The pro-insulin has C-peptide. 
(d) A-peptide and B-peptide of insulin are interconnected by disulphide bridges.
Choose the correct answer from the options given below.

• A. (a) and (d) only
• B. (b) and (d) only
• C. (b) and (c) only
• D. (a), (c) and (d) only

Answer 1

The Correct Option is D

To determine the correct options regarding insulin, let's evaluate each statement individually:

1. (a) C-peptide is not present in mature insulin.
   Mature insulin does indeed not contain the C-peptide. During insulin maturation, the C-peptide is removed from pro-insulin to form the active insulin hormone consisting of A and B chains. Thus, this statement is correct.
2. (b) The insulin produced by rDNA technology has C-peptide.
   This statement is incorrect. rDNA technology is typically used to produce human insulin in its mature form, without C-peptide, similar to naturally occurring insulin. The purpose of recombinant human insulin is to replicate the function of naturally occurring insulin, which does not have the C-peptide.
3. (c) The pro-insulin has C-peptide.
   Pro-insulin is the precursor to insulin and contains the C-peptide linking the A and B chains. During the conversion to active insulin, the C-peptide is cleaved off. Therefore, this statement is correct.
4. (d) A-peptide and B-peptide of insulin are interconnected by disulphide bridges.
   This statement is correct. In the structure of mature insulin, A and B chains are interconnected by disulfide bridges, which are crucial for the molecule's stability and function.

After evaluating each statement, the correct options are (a), (c), and (d). Therefore, the correct answer is:

(a), (c) and (d) only