Recombinant Insulin Production
மறுசீரமைப்பு இன்சுலின் உற்பத்தி
Stop confusing proinsulin with mature insulin. Proinsulin contains an extra C-peptide which is removed during maturation. In NEET, this distinction is the difference between a correct answer and a negative mark.
The idea
Recombinant insulin is produced by inserting DNA sequences encoding human insulin chains A and B into separate E. coli plasmids. These chains are synthesized independently within the bacteria. After extraction, the chains are joined by creating disulfide bonds to form functional, mature human insulin.
Why it matters
It provides a safe, non-immunogenic alternative to animal-derived insulin, which often caused allergic reactions in diabetic patients.
NEET lens
NEET focuses on the 'C-peptide' removal process and the use of E. coli as the host. Remember: Eli Lilly produced this in 1983. Do not confuse the chains; A and B are linked by disulfide bonds, not peptide bonds. This is a high-yield topic; memorize the production steps precisely.
Clinical significance
Insulin is essential for glucose homeostasis. In Type 1 Diabetes Mellitus, the pancreas fails to produce insulin, leading to hyperglycemia. Recombinant human insulin is the life-saving replacement therapy for these patients.
Introduction
Human insulin for diabetes is now produced by genetically engineered bacteria, replacing insulin from slaughtered cattle and pigs, which caused allergies in some patients.
Core concept
Insulin consists of two short polypeptide chains, chain A and chain B, linked together by disulphide bridges. In mammals, including humans, insulin is synthesised as a pro-hormone (pro-insulin) that contains an extra stretch called the C peptide, which is removed during maturation into insulin. The main challenge was getting insulin assembled into a mature form. In 1983, Eli Lilly, an American company, prepared two DNA sequences corresponding to the A and B chains of human insulin and introduced them into plasmids of E. coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulphide bonds to form human insulin.
Go deeper
Genetically engineered insulin is identical to human insulin, so it avoids the allergic reactions seen with animal insulin. Mature insulin has no C-peptide.
From Class 10
People with diabetes need insulin. Today it is made by bacteria that carry the human insulin gene.