HIGH SPECIFIC ACTIVITY LABELING OF INSULIN WITH IODINE-131
Final technical rept., 1 Nov 1962-1 Apr 1963
HAZLETON-NUCLEAR SCIENCE CORP PALO ALTO CA
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Two methods reported in the literature for the labeling of insulin with iodine-131 have been studied using tracer amounts of activity and the results described in this report. Although this study concerned itself with low specific activity insulin, the design of the apparatus and experimental mental techniques are such that high specific activity labeling may be achieved by scaling up with little modification. The two methods stud ied, one described by Yalow and Berson and the other by R. W. Helmkamp and associates, differ essentially in the reagent used in the iodination, the former using iodine in basic solution and the latter iodine monochloride. Our studies seem to indicate that even when tracer amounts of radioactive iodine are used in the preparation of labeled insulin the degree of degradation is in excess of 25. We have shown that there exists a great need for a better method of purification of labeled insulin, conventional techniques being inadequate. Of the several possibilities which suggest themselves, paper chromatography seems the most promising for further study.