title: Characterization of superoxide production from aldehyde oxidase: an important source of oxidants in biological tissues.
abstract: Aldehyde oxidase, a molybdoflavoenzyme that plays an important role in aldehyde biotransformation, requires oxygen as substrate and produces reduced oxygen species. However, little information is available regarding its importance in cellular redox stress. Therefore, studies were undertaken to characterize its superoxide and hydrogen peroxide production. Aldehyde oxidase was purified to >98% purity and exhibited a single band at approximately 290 kDa on native polyacrylamide gradient gel electrophoresis. Superoxide generation was measured and quantitated by cytochrome c reduction and EPR spin trapping with p-dimethyl aminocinnamaldehyde as reducing substrate. Prominent superoxide generation was observed with an initial rate of 295 nmol min(-1) mg(-1). Electrochemical measurements of oxygen consumption and hydrogen peroxide formation yielded values of 650 and 355 nmol min(-1) mg(-1). In view of the ubiquitous distribution of aldehydes in tissues, aldehyde oxidase can be an important basal source of superoxide that would be enhanced in disease settings where cellular aldehyde levels are increased.
authors.affiliation: Center for Biomedical EPR Spectroscopy and Imaging, The Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Internal Medicine, Ohio State University College of Medicine, Columbus, OH 43210, USA.
authors.forename: Tapan Kumar
authors.initials: TK
authors.lastname: Kundu
authors.forename: Russ
authors.initials: R
authors.lastname: Hille
authors.forename: Murugesan
authors.initials: M
authors.lastname: Velayutham
authors.forename: Jay L
authors.initials: JL
authors.lastname: Zweier
mesh_terms: D042931:Aldehyde Oxidase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D045304:Cytochromes c / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008297:Male; D016877:Oxidants / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D051381:Rats; D017207:Rats, Sprague-Dawley; D019097:Spin Trapping; D013481:Superoxides / Q000737:chemistry / Q000378:metabolism*; D013997:Time Factors
chemical_list: D016877:Oxidants; D013481:Superoxides; D045304:Cytochromes c; D006861:Hydrogen Peroxide; D042931:Aldehyde Oxidase