(+/-)-7alpha,8beta-dihydroxy-9beta,10beta-epoxy-7,8,9,10-tetrahydrobenzo(a)-pyrene is an intermediate in the metabolism and binding to DNA of benzo(a)pyrene.

Abstract

The addition of borate buffer to the aqueous methanol used to elute hydrocarbon-deoxyribonucleoside derivatives from an LH 20 Sephadex column resulted in the separation of the products of reaction with DNA of the stereoisomers, (.+-.)-7.alpha.,8.beta.-dihydroxy-9.alpha.,10.alpha.-epoxy- and (.+-.)-7.alpha.,8.beta.-dihydroxy,9.beta.,10.beta.-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrenes, i.e., the syn- and anti-benzo[a]pyrene diolepoxide, respectively. By this technique it was shown that the [rat liver] microsome mediated binding to DNA of benzo[a]pyrene 7,8-dihydrodiol involved exclusively the anti-benzo[a]pyrene diolepoxide. Benzo[a]pyrene binding to DNA that resulted on exposure of BHK21/C13 [hamster kidney] cells to this carcinogen also resulted by reaction of the anti-benzo[a]pyrene diolepoxide. In this case other derivatives, including the syn-benzo[a]pyrene diolepoxide, might also be involved.