title: The Arabidopsis ascorbate peroxidase 3 is a peroxisomal membrane-bound antioxidant enzyme and is dispensable for Arabidopsis growth and development.
abstract: Ascorbate peroxidase (APX) exists as several isoforms that are found in various compartments in plant cells. The cytosolic and chloroplast APXs appear to play important roles in antioxidation metabolism in plant cells, yet the function of peroxisomal APX is not well studied. In this study, the localization of a putative peroxisomal membrane-bound ascorbate peroxidase, APX3 from Arabidopsis, was confirmed by studying the green fluorescent protein (GFP)-APX3 fusion protein in transgenic plants. GFP-APX3 was found to co-localize with a reporter protein that was targeted to peroxisomes by the peroxisomal targeting signal 1. The function of APX3 in Arabidopsis was investigated by analysing an APX3 knockout mutant under normal and several stress conditions. It was found that loss of function in APX3 does not affect Arabidopsis growth and development, suggesting that APX3 may not be an important antioxidant enzyme in Arabidopsis, at least under the conditions that were tested, or the function of APX3 could be compensated by other antioxidant enzymes in plant cells.
authors.affiliation: Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409, USA.
authors.forename: Savitha
authors.initials: S
authors.lastname: Narendra
authors.forename: Sujatha
authors.initials: S
authors.lastname: Venkataramani
authors.forename: Guoxin
authors.initials: G
authors.lastname: Shen
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Vijaya
authors.initials: V
authors.lastname: Pasapula
authors.forename: Yun
authors.initials: Y
authors.lastname: Lin
authors.forename: Dmytro
authors.initials: D
authors.lastname: Kornyeyev
authors.forename: A Scott
authors.initials: AS
authors.lastname: Holaday
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D060387:Ascorbate Peroxidases; D060365:Chloroplast Proteins; D006358:Hot Temperature; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009154:Mutation; D018384:Oxidative Stress; D010544:Peroxidases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D020675:Peroxisomes / Q000201:enzymology*; D016415:Sequence Alignment
chemical_list: D000975:Antioxidants; D029681:Arabidopsis Proteins; D060365:Chloroplast Proteins; D008565:Membrane Proteins; D010544:Peroxidases; C555294:APX3 protein, Arabidopsis; C555297:APXS protein, Arabidopsis; D060387:Ascorbate Peroxidases