Abstract
Putative 'protein nitratases,' which catalyze denitration of peroxynitrite (PN)-treated proteins, were detected in the homogenate/crude extract of rat brains and hearts. Nitratase activity was monitored by the decreased intensity of nitrotyrosine immunoreactive-bands in Western blot and increased nitrate level in dialysate of incubation mixture, which contained homogenate/crude extract, protease inhibitors and a PN-treated substrate, such as treated histone (III-S), BSA or invertase. Enhanced activity of nitratases was noted by preincubating crude extract with Ca2+. In addition, at least two types of nitratases may occur: type I, reductant-dependent, and type II, reductant- independent. Furthermore, upon denitration, the activity of PN-treated invertase increased to the same activity level of the untreated invertase. The overall reaction catalyzed by nitratases for denitration of nitrotyrosine residues in protein could be as follows: Protein-Tyr-NO2 + H2O --> Protein-Tyr-H + H+ + NO3-. The nitration/denitration of protein-tyrosine may be crucial in regulating signal transduction.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Blotting, Western
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Brain / metabolism*
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Brain Chemistry
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Calcium / chemistry
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Calcium / metabolism
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Dialysis
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Enzymes / chemistry
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Enzymes / metabolism*
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Flavin-Adenine Dinucleotide / analogs & derivatives
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Flavin-Adenine Dinucleotide / metabolism
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Glutathione / metabolism
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Glutathione Transferase / metabolism
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Glycoside Hydrolases / chemistry
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Glycoside Hydrolases / drug effects
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Glycoside Hydrolases / metabolism
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Myocardium / chemistry
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Myocardium / metabolism*
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NAD / metabolism
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NADP / metabolism
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Nitrates / analysis
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Nitrates / chemistry
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Nitrates / metabolism*
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Nitrates / pharmacology
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Proteins / chemistry
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Proteins / drug effects
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Proteins / metabolism*
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Rats
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Serum Albumin, Bovine / chemistry
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Serum Albumin, Bovine / drug effects
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Serum Albumin, Bovine / metabolism
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Tissue Extracts / chemistry
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Tissue Extracts / metabolism
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Tyrosine / analogs & derivatives
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Tyrosine / analysis
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Tyrosine / metabolism
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beta-Fructofuranosidase
Substances
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Enzymes
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Nitrates
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Proteins
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Tissue Extracts
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NAD
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Flavin-Adenine Dinucleotide
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1,5-dihydro-FAD
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peroxynitric acid
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Serum Albumin, Bovine
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3-nitrotyrosine
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Tyrosine
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NADP
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Glutathione Transferase
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Glycoside Hydrolases
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beta-Fructofuranosidase
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Glutathione
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Calcium