Monoiodoinsulin PREPARATION, PURIFICATION, AND CHARACTERIZATION OF A BIOLOGICALLY ACTIVE DERIVATIVE SUBSTITUTED PREDOMINANTLY ON TYROSINE A14

摘要: Abstract The iodination of zinc-free insulin was catalyzed by lactoperoxidase, and monoiodoinsulin purified from the reaction mixture chromatography on DEAE-Sephadex (A-25). This fraction demonstrated to be essentially pure criteria polyacrylamide gel electrophoresis, specific radioactivity, neutron activation analysis for iodine content. derivative ultraviolet absorption characteristics expected a monoiodotyrosyl insulin. Circular dichroic immunological studies indicated no significant perturbations in molecule due attachment iodine. Basic hydrolysis subsequent amino acid that 85 90% total associated with 3-monoiodotyrosine, remaining apparently hydrolytic degradation products 3-monoiodotyrosine. Oxidative sulfitolysis followed enzymatic S-sulfo A B chains this substituted predominantly (76%) tyrosine at position 14 chain. biological activity indistinguishable native criterion blood sugar depression alloxan diabetic mice, 70 80% relative mouse convulsion assay. It therefore seems likely absolute integrity A14 is not required expression marked effect zinc both reactivity near circular dichroism noted during course work. In addition, pH substitution examined, method presented characterization mixtures electrophoresis.