The reaction of [14C]iodoacetate with insulin at pH 5.6 and 30° yields a carboxymethylated derivative in 13.8% yield provided zinc is first removed from the insulin. Zinc-insulin reacts very slowly. A pure product can be obtained in which the sole modification, as shown by amino acid analysis, is the carboxymethylation of the two histidyl residues of the B chain. This modification fails to alter the immunologic reactivity of insulin in standard radioimmunoassays but markedly reduces the biological activity of the derivative as measured by glucose oxidation or glycogen synthesis in the isolated rat diaphragm.
|Number of pages||5|
|Publication status||Published - 1973|
ASJC Scopus subject areas