title: Quantitative generation of singlet (1 delta g) oxygen from acidified aqueous peroxynitrite produced by the reaction of nitric oxide and superoxide anion.
abstract: Simple acidification of aqueous alkaline peroxynitrite quantitatively generates singlet (1 delta g) molecular oxygen, detected and quantitated spectroscopically (1270 nm). This observation provides a chemical basis for physiological cytotoxicity of ONOO- generated in the diffusion - controlled reaction of cellular NO. and O2-. The experiments consist of (i) chemical generation of ONOO- from NO. gas and KO2 powder in alkaline aqueous solution; (ii) absorption spectral identification of ONOO- in the near-UV with maximum at 301 nm; (iii) spectroscopic identification of 1O2 by its emission band at 1200-1340 nm with maximum at 1275 nm; and (i.v.) quantification of 1O2 generated in ONOO-/H+ reaction by comparison of the chemiluminescence intensity at 1270 nm with that from H2O2/OCI- reaction that generates 1O2 with unit efficiency at alkaline pH. 1O2 was generated with unit efficiency with respect to ONOO- concentration by the ONOO-/H+ reaction.
authors.affiliation: Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
authors.forename: A U
authors.initials: AU
authors.lastname: Khan
mesh_terms: D004355:Drug Stability; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D009566:Nitrates / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D026082:Singlet Oxygen; D013056:Spectrophotometry, Ultraviolet; D013481:Superoxides / Q000737:chemistry
chemical_list: D009566:Nitrates; D013481:Superoxides; D026082:Singlet Oxygen; C039642:peroxynitric acid; D009569:Nitric Oxide; D010100:Oxygen