Biologically Active Monoiodinated Salmon Calcitonin Purified by Polyacrylamide Gel Electrophoresis

Abstract

¹²⁵I and ¹³¹I salmon calcitonin (sCT) have been purified by polyacrylamide gel electrophoresis. This technique enabled complete separation of labeled from native molecules. Radioimmunoassay of the same amounts of radioactivity before and after purification showed that the specific activity obtained (610 and 575 μCi/μg as a mean for ¹²⁵I and ¹³¹I, respectively) corresponded to the theoretical specific activity for one atom of iodine per molecule (533 for ¹²⁵I and 667 μCi/μg for ¹³¹I). The purified hormone was 90% bound by an excess of specific antibody and retains full biological potency.