Tritiated Angiotensin: Preparation and Purification

Abstract

THE preparation of tritiated angiotensin with a specific activity of 300 µc./mg in 40 per cent yield was reported earlier¹. This peptide was purified by chromatography on carboxymethyl cellulose followed by electrophoresis on paper at pH 2.1. While electrophoresis on paper gave a pure product, the procedure is tedious and time consuming, especially for the preparation of larger amounts. An improved method of purifying tritiated angiotensin substituting partition chromatography on ‘Sephadex G–25’ for paper electrophoresis permitting larger samples to be readily purified has been elaborated. A similar chromatographic procedure has been used by Yamashiro² for purification of oxytocin. The procedure is illustrated with angiotensin tritiated by the Wilzbach technique³ rather than the spark discharge procedure used earlier¹.