Molecular model of insulin molecule

Molecular model of the insulin molecule, ribbon representation. Each chain is shown in a different colour. Insulin molecules consist of two polypeptide chains (A and B) linked by disulphide bonds. Insulin decreases blood glucose concentrations, and increases cell permeability to monosaccharides, amino acids and blood glucose concentrations, and increases cell fatty acids. Defects of insulin are the cause of hyperinsulinemia and type-II diabetes mellitus.