CHEMILUMINESCENCE DETERMINATION OF HYDROPEROXIDES FOLLOWING RADIOLYSIS AND PHOTOLYSIS OF FREE AMINO-ACIDS

Hydroperoxides were determined in selected amino acids using three fre e radical generating systems by a sensitive (50 pmol limit of detectio n) and specific high performance liquid chromatography (HPLC)/chemilum inescence method. UVB and gamma radiation produced significant hydrope roxide formation, particularly in the aromatic amino acids tyrosine an d tryptophan. Hydroperoxide yield was found to be dependent on both am ino acid and irradiation source. Generation of hydrogen peroxide as a by-product of irradiation caused interference with chemiluminescence d etection demonstrating the need for catalase addition, Hydroperoxides were not detectable following metal-catalysed H2O2 breakdown. We sugge st that metal ions could interfere with the detection of hydroperoxide s by causing preferential decomposition. (C) 1998 Federation of Europe an Biochemical Societies.