title: Isolation of new protein phosphatase inhibitors from two cyanobacteria species, Planktothrix spp.
abstract: Two new protein phosphatase inhibitors, oscillamide B (1) and C (2), were isolated from the cyanobacteria Planktothrix (Oscillatoria) agardhii and P. rubescens. The structures of the inhibitors were elucidated by analysis of HRFABMS, 1D and 2D NMR spectra, and chemical degradation. These inhibitors are ureido-containing cyclic peptides and inhibited serine/threonine protein phosphatases PP1 and PP2A. The inhibitory activities were closely related to the Arg and N-Me-Hty residues in the peptides.
authors.affiliation: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-0053, Japan. sanotomo@nies.go.jp
authors.forename: T
authors.initials: T
authors.lastname: Sano
authors.forename: T
authors.initials: T
authors.lastname: Usui
authors.forename: K
authors.initials: K
authors.lastname: Ueda
authors.forename: H
authors.initials: H
authors.lastname: Osada
authors.forename: K
authors.initials: K
authors.lastname: Kaya
mesh_terms: D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification*; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010766:Phosphorylation; D013379:Substrate Specificity
chemical_list: D004791:Enzyme Inhibitors; D010456:Peptides, Cyclic; C436355:anabaenopeptin F; C436352:oscillamide B; C436353:oscillamide C; C436354:oscillamide Y; D010749:Phosphoprotein Phosphatases