Tetrahydrobiopterin‐dependent nitrite oxidation to nitrate in isolated rat hepatocytes

FEBS Letters

Kim, Young-Myeong¹  Lancaster, Jack R.¹ 

[1] Department of Surgery, University of Pittsburgh School of Medicine, 497 Scaife Hall, Pittsburgh, PA 15261, USA

关键词: Nitric oxide;    Nitrite;    Tetrahydrobiopterin;    Nitrogen oxide;    BH4;    tetrahydrobiopterin;    CM;    cytokine mix;    composed of a combination of rat recombinant interferon-γ;    recombinant human interleukin-1β;    and recombinant murine tumor necrosis factor-α;    EPR;    electron paramagnetic resonance spectroscopy;    LPS;    lipopolysaccharide;    NMMA;    N spg-monomethyl-l-arginine;    NOS;    nitric oxide synthase;    NOX −;    total nitrogen oxides (NO2 − + NO3 −);   

DOI  :  10.1016/0014-5793(93)80644-A

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We have found that isolated rat hepatocytes and cell extracts catalyze the stoichiometric conversion of nitrite (either as a product of the oxidation of endogenously synthesized nitric oxide or added as sodium nitrite) to nitrate, which in extracts requires the presence of tetrahydrobiopterin and is inhibited by cyanide but apparently not by carbon monoxide. The reaction is sensitive to heat denaturation and does not involve oxidation of NO₂ ⁻ by a peroxidative or radical oxygen mechanism. These results indicate the presence of a hitherto undescribed mammalian mechanism of inorganic nitrogen oxide oxidation that may be a protective mechanism against one potentially damaging effect of endogenous 'NO production (NO₂ ⁻ formation), and also that assays of NO formation based on NO₂ ⁻ determination alone may be an inaccurate measurement of this activity.

【 授权许可】

Unknown