title: Purification and physicochemical characterization of a recombinant phospholipid hydroperoxide glutathione peroxidase from Oryza sativa.
abstract: Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is an unique antioxidant enzyme that directly reduces lipid hydroperoxides in biomembranes. In the present work, the entire encoding region for Oryza sativa PHGPx was expressed in Escherichia coli M15, and the purified fusion protein showed a single band with 21.0 kD and pI = 8.5 on SDS- and IFE-PAGE, respectively. Judging from CD and fluorescence spectroscopy, this protein is considered to have a well-ordered structure with 12.2% alpha-helix, 30.7% beta-sheet, 18.5% gamma-turn, and 38.5% random coil. The optimum pH and temperature of the enzyme activity were pH 9.3 and 27 degrees C. The enzyme exhibited the highest affinity and catalytical efficiency to phospholipid hydroperoxide employing GSH or Trx as electron donor. Moreover, the protein displayed higher GSH-dependent activity towards t-Butyl-OOH and H(2)O(2). These results show that OsPHGPx is an enzyme with broad specificity for hydroperoxide substrates and yielded significant insight into the physicochemical properties and the dynamics of OsPHGPx.
authors.affiliation: Laboratory of Molecular Biology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Zebin
authors.initials: Z
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Duan
authors.forename: Jin-Yuan
authors.initials: JY
authors.lastname: Liu
mesh_terms: D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005979:Glutathione Peroxidase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D000080662:Phospholipid Hydroperoxide Glutathione Peroxidase; D005979:Glutathione Peroxidase