title: Properties of two toxins isolated from the blue-green alga Microcystis aeruginosa.
abstract: Attempts were made to characterize the two toxins (P-1 and P-2) isolated from the blue-green alga Microcystis aeruginosa, by amino acid analysis, mass spectrometry, 1H- and 13C-NMR. P-2, the major toxin, had a molecular weight of 1044, and consisted of one molecule each of beta-methylaspartic acid, D-Glu, D-Ala, L-Arg, L-Tyr, N-methyldehydroalanine, and 3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda). P-1, with a molecular weight of 994, appeared to have almost the same composition except that it contained L-Leu instead of L-Tyr in P-2. Mass spectrometric studies, along with a negative ninhydrin reaction, indicated that each toxin was a cyclic peptide. P-2 showed an LD99 of 70 micrograms/kg mice when injected i.p. and [alpha]D24 of -72.42 degrees (c = 0.095 in methanol), and was decomposed at around 218 degrees C.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002849:Chromatography, Gas; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008387:Marine Toxins / Q000302:isolation & purification*; D013058:Mass Spectrometry; D046931:Microcystis / Q000032:analysis*; D008970:Molecular Weight
chemical_list: D000596:Amino Acids; D008387:Marine Toxins