Effect of Inorganic Phosphate on the Photoproduction of Hydrogen Peroxide in Frozen Aqueous Solutions of Adenine Derivatives

Abstract

The content of hydrogen peroxide in 2 × 10−4 M aqueous solutions of adenine (A), adenosine (Ado) and adenosine-5'-diphosphate (ADP) containing NaCl (0.1 M) irradiated with near-UV light at 77 K and identical solutions containing added inorganic phosphate (Pi) is determined. It is shown that introducing Pi into the solutions considerably improves the yield of H2O2. The results from detecting H2O2 in the studied systems are compared to estimates of the integral intensities of EPR signals (IntS) of the irradiated solutions before defrosting (and the estimates of content of different components of these spectra, obtained by modeling). It is concluded that the basic producers of H2O2 in the studied systems are aggregates of adenine derivatives that form upon the freezing of aqueous solutions.