Activation of 2,4-diaminotoluene to proximate carcinogens in vitro, and assay of DNA adducts

G. Citro, R. Galati, A. Verdina, S. Marini, R. Zito, B. Giardina

Research output: Contribution to journalArticlepeer-review

Abstract

1. 2,4-Diaminotoluene, which yields adducts with DNA in vivo, has been studied for its ability to form adducts in vitro. Metabolic activation with rat liver post-mitochondrial supernatant gave 300 adducts/106 nucleotides in calf thymus single-stranded DNA, under defined experimental conditions. 2. 2,4-Diaminotoluene-modified DNA and deoxyhomopolymers showed characteristic u.v. absorption spectra, exhibiting hyperchromic effects at 235 and 220 nm, and hypochromic effect at 260 nm. The difference spectra between diamine-modified and untreated DNA, or deoxyhomopolymer, were very similar to the spectrum of 2,4-diaminotoluene alone. 3. 2,4-Diaminotoluene-modified DNA was assayed by ELISA with specific monoclonal antibodies directed against diamine-DNA adducts. Reactions with poly-d(A) or poly-d(A-T) gave no spectral modification, and immunochemical analysis showed that the diamine did not bind to these polynucleotides. On the other hand, in the case of poly-d(G) or poly-d(C-G), strong immunoreactions were observed, demonstrating that the guanine base is involved in the binding of the diamine to DNA. 4. Monoclonal antibodies directed against different diamine-DNA adducts have shown that 80% of the in vitro metabolic activation involves the para amino group of the aromatic diamine.

Original languageEnglish
Pages (from-to)317-325
Number of pages9
JournalXenobiotica
Volume23
Issue number3
DOIs
Publication statusPublished - 1993

ASJC Scopus subject areas

  • Pharmacology
  • Toxicology
  • Biochemistry
  • Health, Toxicology and Mutagenesis
  • Biochemistry, Genetics and Molecular Biology(all)

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