The triplet energy of thymine in DNA.
Norfloxacin (NFX) photosensitizes formation of thymine dimers (T<>T) in DNA, while its N(4') acetyl derivative (ANFX) does not. This is evident from the observation of single-strand breaks after enzymatic treatment with T4 endonuclease V and subsequent gel electrophoresis. The triplet energies of NFX and ANFX are estimated at 273 and 268 kJ/mol, respectively, on the basis of triplet-triplet energy transfer quenching by a set of biphenyl and naphthalene derivatives. Hence, the triplet energy of thymine in DNA (i.e., the value for a photosensitizer to produce T<>T) can be estimated at 270 kJ/mol.
Bosca
Francisco
F
Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica de Valencia, Avda de los Naranjos s/n, 46022 Valencia, Spain.
Lhiaubet-Vallet
Virginie
V
Cuquerella
M Consuelo
MC
Castell
Jose V
JV
Miranda
Miguel A
MA