title: 7-Desmethyl-microcystin-RR, a hepatotoxin from a waterbloom of Microcystis aeruginosa.
abstract: A peptide toxin was isolated from a waterbloom of Microcystis aeruginosa from Lake Frøylandsvatn in Norway. The isolation procedure included liquid and solid phase extraction and reversed phase high performance liquid chromatography. Amino acid analysis yielded D-glutamic acid, D-erythro-beta-methylaspartic acid and D-alanine in equimolar and L-arginine in twofold molar ratios. The presence of dehydroalanine was confirmed by hydrogenation and subsequent amino acid analysis with combined gas liquid chromatography/mass spectrometry. Investigation of the toxin with fast atom bombardment mass spectrometry showed a nominal relative molecular mass of 1023. 3-Amino-9-methoxy-2,6,8-trimethyl-10-phenyl- 4,6-decadienoic acid (Adda) was identified by 1H NMR and 1H, 1H COSY spectroscopy. The structure of the toxin was elucidated as 7-desmethyl-microcystin-RR.
authors.affiliation: Institut für Biologie II, Mikrobiologie, Albert-Ludwigs-Universität, Freiburg, Bundesrepublik Deutschland.
authors.forename: C
authors.initials: C
authors.lastname: Martin
authors.forename: J
authors.initials: J
authors.lastname: Weckesser
authors.forename: T
authors.initials: T
authors.lastname: Ino
authors.forename: W A
authors.initials: WA
authors.lastname: König
authors.forename: O M
authors.initials: OM
authors.lastname: Skulberg
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D008099:Liver / Q000187:drug effects / Q000473:pathology*; D009682:Magnetic Resonance Spectroscopy; D052998:Microcystins; D046931:Microcystis; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification*; D016339:Spectrometry, Mass, Fast Atom Bombardment; D014118:Toxins, Biological / Q000302:isolation & purification*
chemical_list: D052998:Microcystins; D010456:Peptides, Cyclic; D014118:Toxins, Biological; C077788:7-desmethylmicrocystin RR