SEPARATION OF 11 ANGIOTENSIN-II ANALOGS BY CAPILLARY ELECTROPHORESIS WITH A NONIONIC SURFACTANT IN ACIDIC MEDIA

Eleven angiotension II analogs of same chain length were separated by capillary electrophoresis at pH 2.0 with 200 mM Tween 20. All compounds except one pair of angiotensin II ([Sar(1), Gly(8)]- and [Sar(1), Val(5), Ala(8)]-angiotensin II) were baseline-separated, even in the case of peptides with about the same total charge. The migration order of the angiotensin II analogs were determined by the hydrophobicity of the amino acid as long as the difference between amino acids of two peptides is the conservative change. From the study of pH dependency of the separation of these peptides, it was found that the conditions of a low electroosmotic flow under a low pH is effective for the separation of similar peptides.