Oxidation and nitrosylation of oxyhemoglobin by S-nitrosoglutathione via nitroxyl anion.
The reaction between low molecular weight S-nitrosothiols and hemoglobin is often used to synthesize S-nitrosohemoglobin, a form of hemoglobin suggested to be involved in the regulation of vascular oxygen delivery. However, this reaction has not been studied in detail, and several groups have reported a variable co-formation of oxidized methemoglobin (metHb) during synthesis. This study examines the mechanism of metHb formation and shows that nitrosylhemoglobin (HbNO) can also be formed. Generation of metHb and HbNO is largely dependent on the presence of protein thiol groups. We present evidence for a mechanism for the formation of metHb and HbNO involving the intermediacy of nitroxyl anion. Specifically, the reaction of nitroxyl with S-nitrosothiols to liberate nitric oxide and reduced thiol is proposed to be central to the reaction mechanism.
Spencer
Netanya Y
NY
Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Patel
Neil K
NK
Keszler
Agnes
A
Hogg
Neil
N
D000838:Anions; D003300:Copper / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D004566:Electrodes; D004578:Electron Spin Resonance Spectroscopy; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D009569:Nitric Oxide / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D009589:Nitrogen Oxides; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D010108:Oxyhemoglobins / Q000737:chemistry*; D026422:S-Nitrosoglutathione / Q000737:chemistry*; D026403:S-Nitrosothiols / Q000737:chemistry; D013997:Time Factors
D000838:Anions; D006454:Hemoglobins; D009589:Nitrogen Oxides; D010108:Oxyhemoglobins; D026403:S-Nitrosothiols; C103574:S-nitrosohemoglobin; C008657:nitrosyl hemoglobin; D009569:Nitric Oxide; D026422:S-Nitrosoglutathione; D003300:Copper; C039900:nitroxyl; D003545:Cysteine; D009584:Nitrogen; D010100:Oxygen