Preparation and characterization of desoctapeptide-insulin

Desoctapeptide-insulin was prepared by tryptic digestion of insulin and was readily purified by chromatography in urea-containing buffers on columns of DEAE-Sephadex. The preparation was highly purified as judged by electrophoretic and amino acid analyses. The biologic activity of desoctapeptide-insulin was found to be less than 0.2 I.U./mg by mouse convulsion assay, and the immunologic reactivity was found by quantitative immune hemolysis to be about 1% of that of a standard insulin.