What was the challenge for production of insulin using rDNA techniques ?
How did Eli Lilly produce insulin using rDNA technology?

Explanation

The main challenge for production of insulin assembled into a mature form. In 1983, Eli Lilly, an American company prepared two DNA sequences corresponding to A and B, chains of human insulin and introduced them in plasmids of E. coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form hormone insulin.