title: Structure of the peptide antibiotic polypeptin.
abstract: Polypeptin, a basic peptide antibiotic isolated from Bacillus circulans, was separated into two components by countercurrent distribution. The two components, polypeptin A and polypeptin B, had identical amino acid compositions but varied in the structure of the hydroxy acid constituent attached to the alpha-amino group of the peptide chain. Polypeptin A contained 3-hydrosy-4-methylhexanoic acid and polypeptin B contained 3-hydrosy-5-methylhexanoic acid. T-HE STEROCHEMISTRY OF THESE HYDROXY ACIDS WAS NOT DETERMINED. Studies involving partial acid hydrolysis and chemical synthesis are consistent with the lactone sturcture for polypeptin A. Polypeptin B differs only in the position of the methyl group in the hydroxyacyl moiety.
mesh_terms: D000595:Amino Acid Sequence; D055598:Chemical Phenomena; D002621:Chemistry; D003377:Countercurrent Distribution; D006868:Hydrolysis; D006880:Hydroxy Acids; D007536:Isomerism; D011113:Polymyxins / Q000031:analogs & derivatives*
chemical_list: D006880:Hydroxy Acids; D011113:Polymyxins; C013652:polypeptin