ABNORMAL INSULIN-BINDING FRACTION DEMONSTRATED BY THE ELECTROPHORESIS ON ION-EXCHANGE PAPER OF SERA FROM DIABETIC PATIENTS*

Abstract

A cation-exchange resin paper, Amberlite IR-120, was used as the supporting medium for the electrophoresis of serum. The serum protein patterns developed by the bromphenol blue dye were similar in appearance to those observed after filter-paper electrophoresis. Insulin-I131, alone, remained adherent to the origin of the resin paper, but migrated with a mobility that was almost as great as that of serum albumin when the insulin-binding sites of the paper had been saturated by stable insulin. Insulin-I131 in serum from normal subjects and from most of the insulin-responsive diabetic patients migrated with a mobility approximating that of alpha or beta globulins. However, insulin-131 in serum from "true" insulin-resistant diabetic patients migrated in association with the gamma and inter-gamma-beta protein fractions. Thus, distinct physical differences were demonstrated between the serum insulin-binding proteins of insulin-responsive and insulin-resistant diabetic patients.