A method for separating commercial colistin complex into new components: colistins pro-A, pro-B and pro-C.
Commercial colistin was separated into three major components as well as lipid components by reversed phase adsorption chromatography on Diaion HP-20 AG, a macroreticular styrene-divinylbenzene copolymer, without any inorganic salts or detergents, in aqueous-organic solvent as mobile phase. These expected components were colistins A, B and C; there were, however, appreciable differences between these components and colistins A, B and C, isolated by countercurrent distribution. The newly isolated components showed slightly higher potency than colistins A, B and C; their molecular weights, as determined by gel permeation chromatography of 2,4-dinitrophenyl derivatives on TSK-GEL G2000H (mobile phase: dimethylformamide), were also slightly higher. Accordingly, they were tentatively named colistins pro-A, pro-B and pro-C. During purification by countercurrent distribution (solvent system: sec-BuOH - n-BuOH - 0.1 N HCl, 30:6:40), colistin pro-A was converted to colistin A. Similarly, colistin pro-B was converted to colistin B, and colistin pro-C to colistin C. Therefore, we concluded that colistins A, B and C are artifacts.
D000596:Amino Acids / Q000032:analysis; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000494:pharmacology; D001419:Bacteria / Q000187:drug effects; D002845:Chromatography; D002850:Chromatography, Gel; D003091:Colistin / Q000032:analysis* / Q000494:pharmacology; D005227:Fatty Acids / Q000032:analysis
D000596:Amino Acids; D000900:Anti-Bacterial Agents; D005227:Fatty Acids; D003091:Colistin