Electrophoresis of [³⁵S] Sulphated Insulin. Immunological and Biological Properties of the Isolated Electrophoretic Components

Abstract

Reaction of insulin with [³⁵S] sulphuric acid at -18°C yielded a preparation containing 4.5 sulphate ester groups/molecule. The reaction product gave nine bands on electrophoresis at pH 1.7, covering a range of charges from +6 (native bovine insulin) to -2 (sulphated insulin containing eight sulphate groups/molecule). Nine electrophoretically homogeneous fractions of sulphated insulin molecules were isolated. The number of sulphate groups in each fraction was determined and was in agreement with the electrophoretic data. Depending on the degree of sulphation, sulphated insulin had a biological activity of 30-95% that of insulin. The reaction of insulin with bovine insulin antiserum decreased with increasing sulphate content.

Key words

[³⁵S] Sulphated Insulin - Electrophoresis of Sulphated Insulin