Control of NO concentration in solutions of nitrosothiol compounds by light

Photochem Photobiol. 1998 Mar;67(3):282-8.


We studied the thermal and photolytic decomposition of two S-nitrosothiols, S-nitrosoglutathione (GSNO) and S-nitroso-N-acetylpenicillamine (SNAP), in water or propanol solutions. A "concentration clamp" (relatively constant concentration of NO as a function of time) could be implemented in a closed volume by varying the pH, concentration of nitrovasodilator and intensity of the light source. Depending on the conditions, the light either stimulated NO release or sharply decreased NO concentration in the test solutions. Changes in the absorption spectra of GSNO solutions were monitored as a function of light exposure. Generation of superoxide as a product of a photolytic decomposition reaction of S-nitrosothiols and further oxidation of NO is the most likely mechanism for light suppression of NO concentration.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Glutathione / analogs & derivatives*
  • Glutathione / metabolism
  • Glutathione / radiation effects
  • Light*
  • Nitric Oxide / metabolism*
  • Nitroso Compounds / metabolism
  • Nitroso Compounds / radiation effects*
  • Penicillamine / analogs & derivatives*
  • Penicillamine / metabolism
  • Penicillamine / radiation effects
  • Photolysis
  • S-Nitroso-N-Acetylpenicillamine
  • S-Nitrosoglutathione
  • Solutions
  • Spectrophotometry
  • Vasodilator Agents / metabolism
  • Vasodilator Agents / radiation effects*


  • Nitroso Compounds
  • Solutions
  • Vasodilator Agents
  • Nitric Oxide
  • S-Nitrosoglutathione
  • S-Nitroso-N-Acetylpenicillamine
  • Glutathione
  • Penicillamine