title: Interaction of (+/-)-7r,8t-dihydroxy-9t,10t-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene with relaxed circular pBR322 DNA.
abstract: The interaction of (+/-)-BPDE (1) with DNA at neutral pH was investigated by the application of relaxed circular pBR322 DNA. (+/-)-BPDE causes a rapid positive supercoiling of this DNA followed by a slower spontaneous relaxation. The results indicate that there are two clearly discernible types of chemical interactions between 1 and DNA, a rapid intercalative covalent binding and a slower strand breakage. The implications of these findings are discussed.
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D000818:Animals; D001580:Benzopyrenes; D055598:Chemical Phenomena; D002621:Chemistry; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D004270:DNA, Circular; D004278:DNA, Superhelical; D008099:Liver / Q000201:enzymology; D009153:Mutagens; D010957:Plasmids; D051381:Rats
chemical_list: D001580:Benzopyrenes; D004270:DNA, Circular; D004278:DNA, Superhelical; D009153:Mutagens; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D004264:DNA Topoisomerases, Type I