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975879 
Journal Article 
Abstract 
Reaction of glutathione with nitric oxide donors in the presence of protein 
Keszler, A; Zhang, YH; Hogg, N 
2008 
Yes 
Free Radical Biology and Medicine
ISSN: 0891-5849
EISSN: 1873-4596 
45 
Suppl. 
S114-S114 
English 
WOS:000260867900324 
is part of a larger document 3452652 SFRBM's 15th Annual Meeting: Program and Abstracts
S-Nitrosothiols (RSNOs) have been reported to play important roles in the regulation of different cellular processes; however, it is yet unclear how they form in vivo. to better understand this, we examined RSNO formation in model systems. the two major mechanisms of RSNO formation are that N2O3 nitrosates thiols or that NO nitrosates thiyl radicals. We found earlier that due to the reversibility of N2O3 formation from NO and NO2 any intervention in one pathway will have an effect on the other reaction route. the major end-product in the reaction of glutathione (GSH), NO and oxygen is glutathione disulfide and not S-nitrosoglutathione (GSNO), thus oxidation and not nitrosation is the major reaction pathway. in the present work we examined the effect of added protein on GSNO accumulation. According to Nudler et al. (PNAS 97:13543, and 99:5913) hydrophobic protein sub-domains catalyze S-nitrosation. We examined the kinetics of SNO formation in the reaction of NO donors, GSH, and both bovine and human serum albumin. We also studied the dependence of RSNO yield from the levels of GSH and albumin across a wide range of concentration of both species. the overall RSNO and GSNO contents were analyzed using reductive chemiluminescence and HPLC methods, respectively. Our results show that hydrophobic protein sub-domains do not catalyze S-nitrosation of either low molecular weight or protein thiols. Instead, protein, especially when present at high levels, hinders RSNO formation. Blocking sulfhydryl group on the protein does not affect the kinetics of GSNO accumulation. Gel electrophoresis results do not suggest structural changes in the protein during the reaction. We conclude that S-nitrosation of thiol is not enhanced by hydrophobic protein environments as compare to aqueous solution. 
Society for Free Radical Biology and Medicine 15th Annual Meeting 
Indianapolis, IN 
November 19-23, 2008