title: Isolation and characterization of wild-type lipoxygenase LOX(Psa)1 from Pleurotus sapidus.
abstract: The lipoxygenase LOX(Psa) 1 of Pleurotus sapidus, originally investigated because of its ability to oxidize (+)-valencene to the valuable grapefruit aroma (+)-nootkatone, was isolated from the peptidase-rich lyophilisate using a three-step purification scheme including preparative isoelectric focusing and chromatographic techniques. Nano-liquid chromatography electrospray ionization tandem mass spectrometry (nLC-ESI-MS/MS) of the purified enzyme and peptide mass fingerprint analysis gave 38 peptides of the lipoxygenase from P. sapidus. Nearly 50% of the 643 amino acids long sequence encoded by the cDNA was covered. Both terminal peptides of the native LOX(Psa) 1 were identified by de novo sequencing, and the postulated molecular mass of 72.5 kDa was confirmed. With linoleic acid as the substrate, the LOX(Psa)1 showed a specific activity of 113 U mg(-1) and maximal activity at pH 7.0 and 30 degrees C, respectively.
authors.forename: Ina
authors.initials: I
authors.lastname: Plagemann
authors.forename: Ulrich
authors.initials: U
authors.lastname: Krings
authors.forename: Ralf G
authors.initials: RG
authors.lastname: Berger
mesh_terms: D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D002853:Chromatography, Liquid; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D008084:Lipoxygenase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D020076:Pleurotus / Q000201:enzymology*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D018076:DNA, Complementary; D008084:Lipoxygenase