Receiving of iodoinsulin with preserved biological activity

The paper presents a method of receiving iodoinsulin with preserved biological activity. As a raw material recrystallized bovine insulin produced by ''Polfa'' was used. Chloramine T was used as an oxidizing agent in the iodize reaction. Insulin was marked with 125I or 127I in the rate of molar concentration of NaI and insulin 0.6. The obtained product contained about 0.3 of iodine atom per one insulin molecule. Specific radioactivity of the iodoinsulin was between 77 and 147 μCi/μg. Such an insulin was in over 95% precipitable with trichloroacetic acid. Its immunological reactivity varied from 89% to 100% while biological activity, determined with the consumption of glucose by the fatty tissue of epididymis of rat, was 92% +- 24% of the native insulin activity. Half-life time of 125I insulin in the rat blood circulation was determined. Curve of the isotope disappearance was biphasic. Half-life time of the first phase (shorter one) was 0.64 +- 0.2 minute while the longer phase 8.89 +- 2.16 minutes. (author)