Résumé
Promazine derivatives are known to be able to photoinduce,
in vitro, direct single-strand breaks into DNA (Decuyper
etal., Biochem. Pharmac.
33, 4025–4031 (1984)). Using [
32P]end labeled DNA fragments, it is demonstrated that this DNA breakage occurs almost regardless of the nucleotide sequence of the DNA. Using 3′-[
32P]end or 5′-[
32P]end labeled oligonucleotide and enzymatic digestion of the fragments generated, it is demonstrated that the termini generated at the site of the breakage are 5′-phosphate, 3′-phosphate and 3′-termini which are presumed to be 3′-phosphoglycolate. This is consistent with an attack of the sugar moeity of the sugar-phosphate backbone of the DNA by the reactives species generated upon near-u.v. irradiation of promazine derivatives.