Mlcoch J, Fuchs J, Oesch F, Platt K L
Institute of Toxicology, University of Mainz, Germany.
Carcinogenesis. 1993 Mar;14(3):469-73. doi: 10.1093/carcin/14.3.469.
Bay region diolepoxide-DNA adducts of dibenz[a,h]anthracene (DBA) formed in vitro were identified and their absolute stereochemistry was assigned. After activation of [5,12-14C]DBA with liver microsomes obtained from Aroclor 1254 treated male Sprague-Dawley rats in the presence of calf thymus DNA for 1 h, the amount of DNA adducts was found to be 9.9 +/- 2.4 pmol/mg DNA, calculated on the basis of the portion of radioactivity eluted from the HPLC reversed-phase column with a water/acetonitrile gradient. Bay region diolepoxide-DNA adducts represented 27.5% of radioactivity associated with DNA adducts. The absolute configuration of the various adducts was determined from the reaction of the (+)- and (-)-3,4-dihydrodiol after metabolic activation and the reaction of the anti- and syn-3,4-dihydroxy-1,2-epoxy-1,2,3,4-tetrahydrodibenz[a,h]anthracen e with DNA or with the individual deoxyribonucleotides. The main bay region adduct was identified as a deoxyguanosine adduct of (anti)-3S,4R-dihydroxy-1R,2S-epoxy-1,2,3,4-tetrahydrodibenz [a,h]anthracene, a metabolite of (-)-3,4-dihydroxy-3,4-dihydrodi- benz[a,h]anthracene. Anti bay region diolepoxide-deoxyguanosine adducts of DBA contributed to 17.7% and syn diolepoxide-derived deoxyguanosine adducts to 5.8% of adduct-associated radioactivity. The amount of bay region deoxyadenosine adducts was calculated to be 4%. For six of probably eight different deoxyadenosine adducts absolute stereochemistry could be assigned. 32P-Postlabelling experiments revealed a binding of 23 +/- 6 pmol/mg DNA for (-)-3,4-dihydrodiol and of 1.5 +/- 0.4 pmol/mg DNA for (+)-3,4-dihydrodiol of DBA.
对体外形成的二苯并[a,h]蒽（DBA）的湾区二环氧乙烷 - DNA加合物进行了鉴定，并确定了它们的绝对立体化学结构。在用从经多氯联苯混合物1254处理的雄性Sprague-Dawley大鼠获得的肝微粒体激活[5,12-¹⁴C]DBA，并在小牛胸腺DNA存在下反应1小时后，根据用乙腈/水梯度从HPLC反相柱上洗脱的放射性部分计算，发现DNA加合物的量为9.9±2.4 pmol/mg DNA。湾区二环氧乙烷 - DNA加合物占与DNA加合物相关的放射性的27.5%。通过代谢激活后（+）-和（-）-3,4-二氢二醇的反应以及反式和顺式-3,4-二羟基-1,2-环氧-1,2,3,4-四氢二苯并[a,h]蒽与DNA或单个脱氧核糖核苷酸的反应，确定了各种加合物的绝对构型。主要的湾区加合物被鉴定为（反式）-3S,4R-二羟基-1R,2S-环氧-1,2,3,4-四氢二苯并[a,h]蒽的脱氧鸟苷加合物，（反式）-3S,4R-二羟基-1R,2S-环氧-1,2,3,4-四氢二苯并[a,h]蒽是（-）-3,4-二羟基-3,4-二氢二苯并[a,h]蒽的代谢产物。DBA的反式湾区二环氧乙烷 - 脱氧鸟苷加合物占加合物相关放射性的17.7%，顺式二环氧乙烷衍生的脱氧鸟苷加合物占5.8%。计算得出湾区脱氧腺苷加合物的量为4%。对于可能的八种不同脱氧腺苷加合物中的六种，可以确定其绝对立体化学结构。³²P后标记实验显示，DBA的（-）-3,4-二氢二醇与DNA的结合量为23±6 pmol/mg DNA，（+）-3,4-二氢二醇与DNA的结合量为1.5±0.4 pmol/mg DNA。
