Human insulin and their artificial production

Insulin is a peptide hormone produced by β-cells of islets of Langerhans of pancreas. As a prohormone (i.e. Pre-pro-insulin). It was discovered by Sir Edward Sharpey Schafer in 1916, while studying islets of Langerhans. Fredrick Sanger et al in 1954 gave the first complete description of insulin.

Insulin hormone consists of two short polypeptide chains, viz; A-Chain (21 amino acids long) and B-Chain (30 amino acids long). Which are linked together by disulphide bonds or disulphide bridges. The signal peptide cleaves to give proinsulin. Proinsulin has to be further processed to become functional. From proinsulin, the C- peptide is removed at the time of maturation. Therefore, chemically human insulin is a small, simple protein composed of 51 amino acids sequence. The molecular weight of human insulin is about 5808 Da. The gene which codes for insulin hormone is present on chromosome number 11. Insulin is essential for the control of blood sugar levels. Diabetes mellitus is a disease

in which some people cannot make insulin themselves. Insulin production by recombinant DNA technology was designed by Gilbert and Villokomaroff in 1978. Artificial human insulin produced by genetically modified bacterium is in inactive form (i.e. it contains C-peptide). In 1983, Eli Lilly an American company prepared the first successful active insulin artificially. The procedure is as follows;