Discription：Insulin is a double-chain polypeptide hormone secreted by β-cells of pancreatic islets. The α chain and β chain are connected by two interchain disulfide bonds, while the α chain contains an intra-chain disulfide bond. Insulin can activate downstream signaling pathways by binding to insulin receptors, including insulin receptor phosphorylation, IRS-1 phosphorylation, Akt phosphorylation, GSK3β phosphorylation, etc., to promote the uptake, utilization and storage of glucose, amino acids. and fatty acids by cells. Inhibits the breakdown of glycogen, protein or fat. Insulin is a common addition to serum-free media. Human insulin can be used in cultured cells of mice, rats and other mammals, and can also be directly injected into mice or rats for related experimental studies. Recombinant human insulin is a 5.8kDa protein heterodimeric glycoprotein consisting of disulfide-linked B chain and A chain （51 total amino acid） .
