ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Monomerization of thymine dimers photosensitized by aromatic amino acids

P. Balgavý and F. Šeršeň

Department of Analytical Chemistry, Faculty of Pharmacy, Komenský University, CS-832 32 Bratislava

Abstract:  Aromatic amino acids D,L-tryptophan and D,L-phenylalanine photosensitize monomerization of the cis-syn isomer of thymine dimer of the cyclobutane type in aqueous solutions irradiated with light outside the region of the absorption bands of the isolated compounds (from 340 to 380 nm). The yields of the photosensitized monomerization increase many times in a frozen matrix. The yields decrease with increasing ionic strength of the solution and in the presence of KNO₃ as an electron acceptor. From the results it follows that the reaction proceeds through an excited molecular complex ionically dissociated by charge transfer between the dimer and the amino acid. The dimer monomerization involves a radical reaction. The concentration of the complex­es in the solution raises on its freezing.

Full paper in Portable Document Format: 372a243.pdf

Chemical Papers 37 (2) 243–249 (1983)