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.

Step-by-step solution

Insulin is a protein hormone that is composed of two chains, an A-chain having 21 amino acids and a B-chain having 30 amino acids, linked together by disulphide bonds (S-S). Insulin is derived from a 74 - amino acid prohormone molecule called proinsulin having C-peptide and this is removed before the processing of mature insulin and during the production of recombinant insulin, the two chains were separately produced and then linked with each other. C-peptide is absent in mature insulin.