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ROLE OF COMPLEX FORMATION IN THE PHOTOSENSITIZED DEGRADATION OF DNA INDUCED BY N‘‐FORMYLKYNURENINE
Author(s) -
Walrant P.,
Santos R.,
Charlier M.
Publication year - 1976
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1976.tb06792.x
Subject(s) - pyrimidine dimer , chemistry , dna , dimer , thymine , guanine , photochemistry , polynucleotide , xanthine , aqueous solution , pyrimidine , stereochemistry , dna damage , biophysics , nucleotide , biochemistry , organic chemistry , biology , gene , enzyme
— N'‐Formylkynurenine derivatives efficiently bind to DNA or polynucleotides. Homopolynucleotides and DNA display marked differences in the binding process. Association constants are derived which indicate that the oxidized indole ring is more strongly bound to DNA than the unoxidized one. Irradiation of such complexes with wavelengths greater than 320 nm induces pyrimidine dimer formation as well as DNA chain breaks. Complex formation is shown to play an important role in these photosensitized reactions. The photodynamic action of N'‐formylkynurenine on DNA constituents is negligible at neutral pH but guanine and xanthine derivatives are sensitizable at higher pH. Thymine dimer splitting can occur in aggregated frozen aqueous solutions of N'‐formylkynurenine and thymine dimer but this photosensitized splitting is negligible in liquid solutions at room temperature.