苯代谢产物对兔骨髓线粒体RNA合成的抑制作用及其在体外与DNA的共价结合

Inhibition of RNA synthesis by benzene metabolites and their covalent binding to DNA in rabbit bone marrow mitochondria in vitro.

作者信息

Kalf G F, Snyder R, Rushmore T H

出版信息

Am J Ind Med. 1985;7(5-6):485-92. doi: 10.1002/ajim.4700070512.

Abstract

Mitoplasts from rabbit bone marrow cells in vitro incubated with benzene metabolites showed a concentration-dependent inhibition of mitochondrial RNA synthesis. The 50% molar inhibitory concentration for each metabolite was determined to be p-benzoquinone, 2 X 10(-6); phenol, 2.5 X 10(-5); hydroquinone, 5 X 10(-5); catechol, 2 X 10(-3); benzene, 1.6 X 10(-2). Activated metabolites of radiolabeled benzene covalently bound to mitochondrial DNA in vitro. Labeled deoxynucleosides, enzymatically produced from DNA isolated from mitoplasts prelabeled in DNA with [3H]dGTP and exposed to [14C]benzene in vitro, were chromatographed on a Sephadex LH-20 column to obtain deoxynucleoside-adducts. The elution profiles indicated that mtDNA contained seven deoxyguanosine-adducts. A similar experiment in which the mtDNA was prelabeled with [3H]dATP indicated that two deoxyadenosine-adducts of mtDNA were formed from benzene in vitro. Tentative identification of several deoxyguanosine-adducts indicates that p-benzoquinone, hydroquinone, phenol, and 1,2,4-benzenetriol produced from benzene form adducts with guanine.

摘要

体外培养的兔骨髓细胞的线粒体与苯代谢物一起孵育后，线粒体RNA合成受到浓度依赖性抑制。测定每种代谢物的50%摩尔抑制浓度为：对苯醌，2×10⁻⁶；苯酚，2.5×10⁻⁵；对苯二酚，5×10⁻⁵；儿茶酚，2×10⁻³；苯，1.6×10⁻²。放射性标记苯的活化代谢物在体外与线粒体DNA共价结合。将用[³H]dGTP对线粒体DNA进行预标记并在体外暴露于[¹⁴C]苯后分离得到的DNA经酶促产生的标记脱氧核苷，在Sephadex LH - 20柱上进行色谱分析以获得脱氧核苷加合物。洗脱图谱表明线粒体DNA含有七种脱氧鸟苷加合物。用[³H]dATP对线粒体DNA进行预标记的类似实验表明，体外苯可形成线粒体DNA的两种脱氧腺苷加合物。对几种脱氧鸟苷加合物的初步鉴定表明，苯产生的对苯醌、对苯二酚、苯酚和1,2,4 - 苯三酚与鸟嘌呤形成加合物。