RECENT ACHIEVEMENTS IN PHOTOCHEMISTRY OF SOME COMPONENTS AND ANALOGS OF NUCLEIC-ACIDS

The occurrence of a significant reaction between pyrimidine and purine derivatives has recently been shown using dinucleotide monophosphates and related analogues irradiated with conventional monophotonic far-U V light. This reaction gives a new insight into the photochemical beha viour of nucleic acids and may have mutagenic and lethal consequences in vivo. Photoreactions of amino acids and pyrimidines, as models of n ucleic acid-protein cross-linking, play a significant role in the unde rstanding of the deleterious effects of UV irradiation on cells. Unfor tunately, only in a few cases have the photo-cross-linked products bee n identified unequivocally. Increasing interest in the application of powerful laser sources for the investigation of nucleic acids and thei r components has been prompted by the possibility of free radical gene ration. Ultrahigh intensity laser radiation has made it possible to id entify the main products resulting from the reactions of nucleic acid components of DNA and DNA itself with radicals such as e(aq)(-), H and OH. The luminescence properties of new nucleoside derivatives, photoc hemically synthesized in our laboratory and emitting in the visible re gion, are presented and discussed.