The synthesis of the octapeptide~-aspartyl-~-arg~ nyl-~-valyl-~-tyrosyl-~-isoleucyl-~-histidyl- ~-prol~~ l-~-phenylalanine, using known methods, is described here. The final, crude product was purified by countercurrent distribution and characterized by analysis of its amino acid composition, Rr values and distribution coefficients. Biological activity and specific activity of our final purified product were very similar to the angiotonin octapeptide ...