A brain nitric oxide synthase study in the rat: production of a nitroso-compound NA and absence of nitric oxide synthesis.
The products of brain NO-synthase (NOS) were studied by different analytical techniques with the same incubation conditions. Voltammetric techniques used a micro cell containing NOS and its substrate (10 mM arginine). Using porphyrin microelectrodes with differential pulse amperometry nitric oxide (NO) was not detected when nafion membrane was present (less than 0.3 muM). Nitrite was detected with the same microelectrode without membrane (0.42 mM). Differential pulse voltammetry (DPV) with micro carbon electrode detected a nitroso-compound (NA) in reduction (1 mM) and not NO. In oxidation the observed DPV peak was due to nitrite (0.43 mM). Citrulline was detected by high performance liquid chromatography (0.51 mM). Using Diels Alder reaction in NOS preparation a NA-cycloadduct was observed by capillary electrophoresis (0.2 mM) and mass spectrometry (0.22 mM). Diels Alder reaction is the reaction of the identification of the nitroso group. NA-cycloadduct degradation by retro Diels Alder reaction gave equimolar concentrations of citrulline and nitrite without NO production. These observations lead us to affirm that NOS synthesizes NA.
Meulemans
Alain
A
Faculté de Médecine Xavier Bichat, Laboratoire de Biophysique, 16 rue Henri Huchard, Paris 75018, France. alain.muelemans@voila.fr
D000818:Animals; D001120:Arginine / Q000378:metabolism*; D001921:Brain / Q000201:enzymology*; D002956:Citrulline / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D019335:Nitroarginine / Q000378:metabolism*; D009603:Nitroso Compounds / Q000378:metabolism*; D051381:Rats
D009573:Nitrites; D009603:Nitroso Compounds; D019335:Nitroarginine; D002956:Citrulline; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase