title: Heterologous expression and characterization of a proxidomal ascorbate peroxidase from Populus tomentosa.
abstract: The present study reported for the first time, cloning, expression and characteristics of a Proxidomal APX gene (PpAPX) from Populus tomentosa. The PpAPX gene encodes a protein of 287 amino acid residues with a calculated molecular mass of 31.58 kDa. The over-expressed recombinant PpAPX protein showed high activity towards the substrates ascorbate aicd (ASA) and H(2)O(2). At fixed ASA concentrations, the K (m) and V (max) values were 0.12 +/- 0.01 mM and 23.4 +/- 4.2 mmol/min mg for H(2)O(2). And at fixed H(2)O(2) concentrations, the K (m) and V (max) values were 0.53 +/- 0.04 mM and 20.0 +/- 2.3 mmol/min mg for ASA.
authors: Beijing Forestry University, Beijing Haidian district, Beijing 100083, People's Republic of China. Luhai1974@yahoo.com
authors: Hai
authors: H
authors: Lu
authors: Rui-Li
authors: RL
authors: Han
authors: Xiang-Ning
authors: XN
authors: Jiang
mesh_terms: D000595:Amino Acid Sequence; D060387:Ascorbate Peroxidases; D001205:Ascorbic Acid / Q000378:metabolism; D001483:Base Sequence; D030541:Databases, Genetic; D004926:Escherichia coli / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010544:Peroxidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D032107:Populus / Q000201:enzymology* / Q000235:genetics; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D010940:Plant Proteins; D011994:Recombinant Proteins; D006861:Hydrogen Peroxide; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D001205:Ascorbic Acid