HETEROGENEITY OF INSULIN: I. ISOLATION OF A CHROMATOGRAPHICALLY PURIFIED, HIGH-POTENCY INSULIN AND SOME OF ITS PROPERTIES

Abstract

A slight improvement in the chromatography of insulin on Amberlite IRC-50 resin in 7 M urea −0.13 M sodium phosphate buffer, pH 6.05, at 3 °C revealed the presence of at least four components.The major component was found to have a potency greater than that of any other purified insulin hitherto reported and substantiated. The biological activity of the minor components varied from a value close to that of the starting insulin down to very low or negligible values, indicating a loss of biological activity with increasing chemical degradation. The potency studies were quantitative.Starch-gel electrophoresis showed that the main component was not completely homogeneous, traces of other components being present.A highly fluorescent, colored material was separated from among the minor components and may be of interest in relation to allergy produced by some insulins.The separation reported here is discussed in relation to other fractionation procedures.