Perferryl complex of nitric oxide synthase: role in secondary free radical formation.
Neuronal nitric oxide synthase (NOS I) has been shown to generate nitric oxide (NO*) and superoxide (O(2)*-)during enzymatic cycling, the ratio of each free radical is dependent upon the concentration of L-arginine. Using spin trapping and electron paramagnetic resonance (EPR) spectroscopy, we recently reported that NOS I can oxidize ethanol (EtOH) to alpha-hydroxyethyl radical (CH(3)*CHOH). We speculated that the perferryl complex of NOS, (NOS-[Fe(5+)[double bond]O](3+)) was responsible for the generation of CH(3)*CHOH. Using potassium monopersulfate (KHSO(5)) to oxidize the heme of NOS I to NOS-[Fe(5+)[double bond]O](3+), we were able to demonstrate that this perferryl complex can oxidize L-arginine to L-citrulline and NO*. Even in the absence of L-arginine, EtOH was oxidized to CH(3)*CHOH by NOS-[Fe(5+)[double bond]O](3+). Sodium cyanide (NaCN), a heme blocker, inhibited the formation of CH(3)*CHOH by NOS.
Porasuphatana
Supatra
S
Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, 21201, USA.
Tsai
Pei
P
Pou
Sovitj
S
Rosen
Gerald M
GM
D001120:Arginine / Q000378:metabolism; D001665:Binding Sites; D002250:Carbon Radioisotopes; D002956:Citrulline / Q000096:biosynthesis; D004578:Electron Spin Resonance Spectroscopy; D000431:Ethanol / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry; D006418:Heme / Q000037:antagonists & inhibitors / Q000737:chemistry; D006801:Humans; D007501:Iron / Q000737:chemistry; D009249:NADP; D019001:Nitric Oxide Synthase / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D010084:Oxidation-Reduction; D017680:Potassium Compounds; D011994:Recombinant Proteins / Q000378:metabolism; D012966:Sodium Cyanide / Q000494:pharmacology; D019097:Spin Trapping; D013431:Sulfates
D002250:Carbon Radioisotopes; D005609:Free Radicals; D017680:Potassium Compounds; D011994:Recombinant Proteins; D013431:Sulfates; C066318:perferryl iron; D002956:Citrulline; D000431:Ethanol; D006418:Heme; D009249:NADP; C009007:potassium persulfate; D001120:Arginine; D007501:Iron; C496320:NOS1 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D012966:Sodium Cyanide