title: Microcystin LR degradation by Pseudomonas aeruginosa alkaline protease.
abstract: We isolated several species of bacteria from the surface water of a Japanese lake. Of the isolated bacteria, Pseudomonas aeruginosa was the only species which could degrade microcystin LR in vitro. Microcystin LR decreased to 4.5% of the spiked microcystin LR quantity in the P. aeruginosa culture, and was metabolized to (2S, 3S, 8S)-3-amino-2, 6, 8-trimethyl-10-phenyldeca-4E, 6E-dienoic acid (DmADDA). It was possible that P. aeruginosa hydrolysed nucleophilically the peptide bond of microcystin LR. We examined if pyochelin, pyocyanin and alkaline protease produced by P. aeruginosa affected the reduction of microcystin LR. In the result, DmADDA was produced from microcystin LR in the presence of 100 microM H2O2 and 100 microM each of pyochelin, pyocyanin or both. However, the production of DmADDA was slight (2 to 12 mole%). After treatment with P. aeruginosa alkaline protease, DmADDA was produced 75 mole% from microcystin LR. Therefore, we concluded that microcystin was degraded mainly by the action of P. aeruginosa alkaline protease.
authors.affiliation: Department of Pathology and Bacteriology, Fukuoka Institute of Health and Environmental Sciences, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Takenaka
authors.forename: M F
authors.initials: MF
authors.lastname: Watanabe
mesh_terms: D000596:Amino Acids / Q000032:analysis; D003470:Culture Media; D004791:Enzyme Inhibitors / Q000378:metabolism*; D007564:Japan; D008387:Marine Toxins / Q000378:metabolism*; D052998:Microcystins; D010456:Peptides, Cyclic / Q000378:metabolism*; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D012697:Serine Endopeptidases / Q000378:metabolism*
chemical_list: C093163:3-amino-9-methoxy-10-phenyl-2,6,8-trimethyldeca-4,6-dienoic acid; D000596:Amino Acids; D003470:Culture Media; D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; C038495:Pseudomonas serine proteinase; D012697:Serine Endopeptidases; C057862:cyanoginosin LR