¹⁸O-Labeled nitrous acid and nitrite: Synthesis, characterization, and oxyhemoglobin-catalyzed oxidation to ¹⁸O-labeled nitrate.
We describe a simple laboratory method for specific labeling of nitrite with ¹⁸O for use in chemical and biochemical studies in the area of nitric oxide research. NaNO₂ (0.1 mmol) is diluted in H₂¹⁸O (45 μl) and acidified with HCl (1 μl, 5 M), and the solution is allowed to equilibrate. Subsequently, the sample is mixed by vortexing with ethyl acetate (500 μl), and the organic phase is dried over anhydrous Na₂SO(4). Ethyl acetate is evaporated to dryness, and the residue is reconstituted in phosphate-buffered saline. In human blood hemolysate, oxyhemoglobin (HbFe¹⁶O₂) was shown to oxidize N¹⁸O₂⁻ to ¹⁶ON¹⁸O₂⁻.
Institute of Clinical Pharmacology, Hannover Medical School, 30625 Hannover, Germany.
Anke
A
Böhmer
Anja
A
Mitschke
Anna
A
Reib
Frank-Mathias
FM
Gutzki
Dimitrios
D
Tsikas
D002384:Catalysis; D006801:Humans; D007553:Isotope Labeling / Q000379:methods*; D009569:Nitric Oxide / Q000737:chemistry*; D009573:Nitrites / Q000737:chemistry*; D010084:Oxidation-Reduction; D010103:Oxygen Isotopes / Q000737:chemistry*; D010108:Oxyhemoglobins / Q000737:chemistry*
D009573:Nitrites; D010103:Oxygen Isotopes; D010108:Oxyhemoglobins; D009569:Nitric Oxide