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Tetrahydrobiopterin‐dependent nitrite oxidation to nitrate in isolated rat hepatocytes
Author(s) -
Kim Young-Myeong,
Lancaster Jack R.
Publication year - 1993
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(93)80644-a
Subject(s) - chemistry , nitrite , tetrahydrobiopterin , nitric oxide , cyanide , carbon monoxide , sodium nitrite , nitrate , oxygen , inorganic chemistry , biochemistry , methemoglobin , hemoglobin , nitric oxide synthase , catalysis , organic chemistry
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 NO 2 − 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 (NO 2 − formation), and also that assays of NO formation based on NO 2 − determination alone may be an inaccurate measurement of this activity.