Journal
FREE RADICAL BIOLOGY AND MEDICINE
Volume 45, Issue 5, Pages 578-584Publisher
ELSEVIER SCIENCE INC
DOI: 10.1016/j.freeradbiomed.2008.04.036
Keywords
heme; peroxidase; hydroxylamine; N-hydroxy-L-arginine; nitroxyl; suffinamide
Funding
- National Institutes of Health National Cancer Institute
- Center for Cancer Research (DW)
- National Institutes of Health [R01-GM076247]
Ask authors/readers for more resources
The chemical reactivity, toxicology, and pharmacological responses to nitroxyl (HNO) are often distinctly different from those of nitric oxide (NO). The discovery that HNO donors may have pharmacological Utility for treatment of cardiovascular disorders such as heart failure and ischemia reperfusion has led to increased speculation of potential endogenous pathways for HNO biosynthesis. Here, the ability of heme proteins to utilize H2O2 to oxidize hydroxylamine (NH2OH) or N-hydroxy-L-arginine (NOHA) to HNO was examined. Formation of HNO was evaluated with a recently developed selective assay in which the reaction products ill the presence of reduced glutathione (GSH) were quantified by HPLC. Release of HNO from the heme pocket was indicated by formation of sulfinamide (GS(O)NH2), While the yields of nitrite and nitrate signified the degree of intramolecular recombination of HNO with the heme. Formation of GS(O)NH2 was observed upon oxidation of NH2OH, whereas NOHA, the primary intermediate in oxidation of L-arginine by NO synthase, was apparently resistant to oxidation by the heme proteins utilized. In the presence of NH2OH, the highest yields of GS(O)NH2 were observed with proteins in which the heme was coordinated to a histidine (horseradish peroxidase, lactoperoxidase, myeloperoxidase, myoglobin, and hemoglobin) in contrast to a tyrosine (catalase) or cysteine (cytochrome P450). That peroxidation of NH2OH by horseradish peroxidase produced free HNO, which was able to affect intracellular targets, was verified by conversion of 4,5-diaminofluorescein to the corresponding fluorophore within intact cells. (c) Published by Elsevier Inc.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available