TY - JOUR
T1 - Structure elucidation of a 6-methylbenzo[a]pyrene-DNA adduct formed by horseradish peroxidase in vitro and mouse skin in vivo
AU - Rogan, Eleanor G.
AU - Hakam, Alaeddin
AU - Cavalieri, Ercole L.
N1 - Funding Information:
This work was supported by grant RO1 CA25176 from the National Cancer Institute. We thank Dr. Donald L. Nagel for recording the NMR spectra of the adduct, Dr. William M. Baird for the kind gift of \[14C\]BPd iol-epoxide-dG adduct and Ms. Mardelle Susman for editorial assistance.
PY - 1983/10/15
Y1 - 1983/10/15
N2 - Activation of polycyclic aromatic hydrocarbons (PAH) by horseradish peroxidase (HRP) with H2O2 has been studied as a model system for one-electron oxidation. This peroxidase has been used to catalyze binding of 6-[14C]methylbenzo[a]pyrene (BP-6-CH3) to DNA, which was purified, hydrolyzed to deoxyribonucleosides and analyzed by high pressure liquid chromatography (HPLC). The predominant hydrocarbon-DNA adduct observed was identified as BP-6-CH3 bound at the 6-methyl group to the 2-amino group of dG, confirming that activation by HRP occurs by one-electron oxidation. When DNA from mouse skin treated in vivo with [14C]BP-6-CH3 was purified, hydrolyzed and analyzed by HPLC, a profile was observed which was qualitatively similar to that from the peroxidase system. In particular, the identified adduct with the hydrocarbon bound at the 6-methyl group to the 2-amino group of dG was obtained. These results demonstrate that one-electron oxidation is the mechanism of activation by HRP for aromatic hydrocarbons and indicate that the same mechanism may occur in mouse skin, a target tissue for hydrocarbon carcinogenesis.
AB - Activation of polycyclic aromatic hydrocarbons (PAH) by horseradish peroxidase (HRP) with H2O2 has been studied as a model system for one-electron oxidation. This peroxidase has been used to catalyze binding of 6-[14C]methylbenzo[a]pyrene (BP-6-CH3) to DNA, which was purified, hydrolyzed to deoxyribonucleosides and analyzed by high pressure liquid chromatography (HPLC). The predominant hydrocarbon-DNA adduct observed was identified as BP-6-CH3 bound at the 6-methyl group to the 2-amino group of dG, confirming that activation by HRP occurs by one-electron oxidation. When DNA from mouse skin treated in vivo with [14C]BP-6-CH3 was purified, hydrolyzed and analyzed by HPLC, a profile was observed which was qualitatively similar to that from the peroxidase system. In particular, the identified adduct with the hydrocarbon bound at the 6-methyl group to the 2-amino group of dG was obtained. These results demonstrate that one-electron oxidation is the mechanism of activation by HRP for aromatic hydrocarbons and indicate that the same mechanism may occur in mouse skin, a target tissue for hydrocarbon carcinogenesis.
KW - Carcinogenic activation
KW - DNA adduct structure
KW - Horseradish peroxidase
KW - Mouse skin
KW - One-electron oxidation
KW - Polycyclic aromatic hydrocarbons
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U2 - 10.1016/0009-2797(83)90151-5
DO - 10.1016/0009-2797(83)90151-5
M3 - Article
C2 - 6640783
AN - SCOPUS:0021014376
VL - 47
SP - 111
EP - 122
JO - Chemico-Biological Interactions
JF - Chemico-Biological Interactions
SN - 0009-2797
IS - 1
ER -