Insulin, Human Recombinant

Insulin is a double-chain (α, β) polypeptide hormone secreted by islet β cells in the pancreas. It consists of 51 amino acids, of which the α chain contains 21 amino acids and the β chain contains 30 amino acids. The two chains are connected by two pairs of disulfide bonds, and the α chain itself also contains a pair of disulfide bonds. The secretion process of insulin is: the amino terminus of preproinsulin carries a 23-30 amino acid signal peptide. This signal peptide can transfer preproinsulin to the endoplasmic reticulum, and then is immediately cut off to release proinsulin. Proinsulin is composed of insulin β chain, C-peptide and α chain. The released proinsulin is immediately transferred to the Golgi apparatus, where it is packaged and converted into insulin, and is released into the blood together with C-peptide. Insulin is the only protein hormone known in the body that can lower blood sugar. It is not only responsible for regulating the uptake, utilization and storage of glucose, amino acids and fatty acids by cells, but also inhibits the degradation of glycogen, protein and fat.