Human insulin (Novo): chemistry and characteristics.

The amino acid sequence of human insulin was published in 1960. The structure was first confirmed in 1982 by x-ray crystallography, in which complete overlaps of x-ray diffraction patterns were achieved on exposures of insulin from human pancreas and human insulin prepared from porcine insulin. Additional complementary identity tests like HPLC and immunochemical cross-reactivity with anti-insulin sera have substantiated the identity of insulin from human pancreas with human insulin prepared from porcine insulin. Human insulin (Novo) has been prepared from crude porcine insulin by intertwining the chromatographic purification processes for making monocomponent porcine and bovine insulin with two chemical reactions; a trypsin-catalyzed transpeptidation reaction and a nonenzymatic cleavage of an ester bond. The human insulin thus obtained complied with the purity specifications of the monocomponent porcine and bovine insulins. The physico-chemical properties of human insulin are similar to those of porcine insulin, hence the analogous preparations for therapy (Actrapid, Monotard, and Protaphane) can be made. Human insulin shares the biologic characteristics of the other monocomponent insulins, i.e., higher potency per milligram of dry insulin and negligible immunogenicity in the rabbit test in comparison to the conventional insulins.