Separation of methylated and non-methylated cyanoginosin-LR homologues of the cyanobacterium Microcystis aeruginosa strain PCC 7806 by reversed-phase medium-pressure liquid chromatography

Abstract

Cyanoginosins produced by Microcystis aeruginosa sp. are toxic cyclic heptapeptides with molecular weights of about 1000 dalton. Microcystis aeruginosa strain PCC 7806 proved to synthesize a methylated and non-methylated cyanoginosin-LR. A reversed-phase medium-pressure liquid cromatographic method was developed to separate the two cyanoginosin homologues on a preparative scale. The influence of chromatographic conditions on the separation such as solvent system, gradient parameters, flow-rate and temperature was investigated systematically. After optimization, up to 1.5 mg of the two compounds could be separated completely within 40 min.