## Abstract Chemical conversion of generally tritiated benzo (a) pyrene to 6 and 1,6‐substituted derivatives resulted in 30% and 48% loss of tritium respectively. Metabolism of [^3^H], [^14^C]‐benzo (a) pyrene by rat liver microsomes yielded 3‐hydroxybenzo (a) pyrene with 30% loss of tritium, a mix
The binding of benzo(a)pyrene to DNA components of differing sequence complexity
✍ Scribed by P. Jack; P. Brookes
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- French
- Weight
- 708 KB
- Volume
- 25
- Category
- Article
- ISSN
- 0020-7136
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
An examination has been made of the binding, both in vitro and in vivo of the benzo(a)pyrene (BP) adduct to DNA components of differing sequence complexity. Annealing was performed at low renaturation temperatures in the presence of high concentrations of formamide to minimize hydrocarbon‐induced depurination. BHK‐DNA was modified in vitro using a tritiated derivative of the ultimate carcinogenic metabolite of BP, 7α,8β‐di‐hydroxy‐9β,10β‐epoxy‐7,8,9, 10‐tetrahydrobenzo(a)pyrene (BPDE). Co‐renaturation of this modified DNA with [^14^C]‐thymidine‐labelled BHK‐DNA demonstrated that the hydrocarbon adduct did not interfere with strand annealing and showed that the BP adduct was distributed randomly throughout all DNA sequence classes. However, when the DNA of cells in culture was modified by [^3^H]BP, following metabolic activation, and mixed with [^14^C]‐thymidine‐labelled DNA, a small but reproducible difference in the renaturation of the two labels was found. This difference in renaturation profiles was not due to base‐compositional effects since a similar result was found when the alternate ^14^C‐label was present in guanine bases, the principal site of BP modification. The small difference in the renaturation of the two radioactive labels indicated an enrichment of the hydrocarbon on the most rapidly‐renaturing sequence components (the palindromic and highly repetitive sequences) where it amounted to between 19 and 64% increased modification.
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## Abstract A study of the liver microsome‐mediated binding to added DNA of the phenol metabolites of benzo (a)‐pyrene (BP‐OH) and of 7,8‐dihydro‐7,8‐dihydroxybenzo (a)pyrene (BP‐7,8‐diol) suggested that as in the case of BP itself the reaction was catalysed by the enzyme aryl hydrocarbon hydroxyla
## Abstract Individual metabolites of benzo (a)pyrene were isolated from rat liver microsomal incubation of the parent hydrocarbon, and subsequently bound to DNA in separate incubations with microsomes. Of the metabolites examined, by far the greatest binding resulted with 7,8‐dihydro‐7,8‐dihydroxy
## Tritium-labelled benzo[a]pyrene ([3H]BaP ) was applied to mouse skin in acetone or mineral oils of difFering viscosity. Epidermal DNA and protein were extracted &er 24 or 48 h and the degree of adduct formation determined by the radioactivity present. When [3H]BaP was applied in acetone, the d
Previous studies indicated that DNA adducts formed by a carcinogenic diol epoxide, 7r,8t-dihydroxy-9t, 10t-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE), can increase the affinity of the transcription factor Sp1 for DNA sequences that are not normally specific binding sites. It was suggested that a