Recombinant human Insulin (rHu Insulin) is identical in function and structure to the native human sequence. A hormone consisting of two polypeptide chains, rHu Insulin′s A-chain (21 amino acids) and B-chain (30 amino acids) are covalently linked by disulfide bonds between cysteine residues. This genetically engineered human insulin is a full sequence molecule produced in baker’s yeast by recombinant DNA technology. rHu Insulin is a two-chain polypeptide hormone produced by the β-cells of pancreatic islets. Its molecular weight is ~5800 Da. The α and β chains are joined by two interchain disulfide bonds. The α chain contains an intrachain disulfide bond. Insulin regulates the cellular uptake, utilization, and storage of glucose, amino acids, and fatty acids and inhibits the breakdown of glycogen, protein, and fat.