Write a brief note on genetically engineered insulin.

Hint: Insulin is prepared for medicinal purposes on a large scale by recombinant DNA ( rDNA) technology. It was first manufactured by an American biotech corporation in 1983. The name of the trademark is Humulin and it is licensed to Eli Lilly, the company that first manufactured it.

Complete Answer:
In the plasmids of non-pathogenic E.coli strains, genes which code for functional A and B insulin peptides were inserted. Both chains are separately formed and subsequently joined by disulfide linkages.
Insulin has been used in treating diabetes for many years. By taking insulin, diabetes is well controlled. Previously, insulin was derived from the pancreas of cattle and pigs that were killed. It had many drawbacks. It has been used in certain individuals to induce allergic reactions and other immune responses because of its foreign origin. Another challenge was to cater to the ever-growing demand and output on a wide scale.
The development of insulin by recombinant DNA technology was carried out to resolve this and it has proved to be very beneficial. It was the first recombinant medicine in the USA to be used.


Note:
- Biopharming for the manufacture of insulin is being investigated. In safflower plants, researchers succeeded in inserting insulin genes. It will assist in reducing the cost of production.
- Insulin is a protein hormone that is synthesized by pancreatic beta cells. It's developed as a prohormone, i.e. Preproinsulin. Preproinsulin to deliver proinsulin, the signal peptide cleaves. To become functional, proinsulin has to be further processed. In addition to 'A 'and' B 'peptides, proinsulin contains another peptide chain known as' C 'peptide, which is necessary for its functionality. The C peptide is extracted from the proinsulin at the time of maturation.
-No C peptide is found in the genetically modified insulin.