Document Detail


Nitric oxide production from nitrite occurs primarily in tissues not in the blood: critical role of xanthine oxidase and aldehyde oxidase.
MedLine Citation:
PMID:  18424432     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Recent studies have shown that nitrite is an important storage form and source of NO in biological systems. Controversy remains, however, regarding whether NO formation from nitrite occurs primarily in tissues or in blood. Questions also remain regarding the mechanism, magnitude, and contributions of several alternative pathways of nitrite-dependent NO generation in biological systems. To characterize the mechanism and magnitude of NO generation from nitrite, electron paramagnetic resonance spectroscopy, chemiluminescence NO analyzer, and immunoassays of cGMP formation were performed. The addition of nitrite triggered a large amount of NO generation in tissues such as heart and liver, but only trace NO production in blood. Carbon monoxide increased NO release from blood, suggesting that hemoglobin acts to scavenge NO not to generate it. Administration of the xanthine oxidase (XO) inhibitor oxypurinol or aldehyde oxidase (AO) inhibitor raloxifene significantly decreased NO generation from nitrite in heart or liver. NO formation rates increased dramatically with decreasing pH or with decreased oxygen tension. Isolated enzyme studies further confirm that XO and AO, but not hemoglobin, are critical nitrite reductases. Overall, NO generation from nitrite mainly occurs in tissues not in the blood, with XO and AO playing critical roles in nitrite reduction, and this process is regulated by pH, oxygen tension, nitrite, and reducing substrate concentrations.
Authors:
Haitao Li; Hongmei Cui; Tapan Kumar Kundu; Wael Alzawahra; Jay L Zweier
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2008-04-18
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  283     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2008 Jun 
Date Detail:
Created Date:  2008-06-23     Completed Date:  2008-08-18     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  17855-63     Citation Subset:  IM    
Affiliation:
Center for Biomedical EPR Spectroscopy and Imaging, Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, OH 43210, USA. haitao.li@osumc.edu
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MeSH Terms
Descriptor/Qualifier:
Aldehyde Oxidase / chemistry*
Animals
Electron Spin Resonance Spectroscopy
Gene Expression Regulation, Enzymologic*
Hydrogen-Ion Concentration
Liver / metabolism
Male
Models, Biological
Myocardium / metabolism
Nitric Oxide / metabolism*
Nitrites / metabolism*
Rats
Rats, Sprague-Dawley
Substrate Specificity
Xanthine Oxidase / chemistry*
Grant Support
ID/Acronym/Agency:
HL 38324/HL/NHLBI NIH HHS; HL 63744/HL/NHLBI NIH HHS; HL 65608/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Nitrites; 10102-43-9/Nitric Oxide; EC 1.17.3.2/Xanthine Oxidase; EC 1.2.3.1/Aldehyde Oxidase
Comments/Corrections

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