Meinl Walter, Meerman John H N, Glatt Hansruedi
German Institute of Human Nutrition, Department of Toxicology, Arthur-Scheunert-Allee 114-116, 14558 Potsdam-Rehbrücke, Germany.
Pharmacogenetics. 2002 Dec;12(9):677-89. doi: 10.1097/00008571-200212000-00002.
Various enzymatically formed sulfuric acid esters are chemically reactive and mutagenic. This metabolic activation pathway is not detected in standard in-vitro mutagenicity test systems. We describe the construction of Salmonella typhimurium TA1538-derived strains expressing alloenzymes *1, *2, *3, *5, 6 of human sulfotransferase 1A2 (SULT1A2). The reference compounds, 1-hydroxymethylpyrene (1-HMP), N-hydroxy-2-acetylaminofluorene (OH-AAF) and 2-hydroxylamino-5-phenylpyridine (OH-APP), were activated to mutagens in these strains. Their activity differed 7- to 16-fold between strains expressing various alloenzymes. It was strongest and weakest in the strains expressing the common alloenzymes, 1 and 2, respectively. The SULT1A2 protein expression levels, and the V(max) and K(m) values with the reference substrate 4-nitrophenol, varied 2.5-, 4-, and 110-fold, respectively, in cytosolic preparations from strains TA1538-SULT1A21 and 2. Strains with varying protein levels were constructed via insertion of silent mutations in the 5'-part of the cDNA. TA1538-SULT1A21Z and TA1538-SULT1A22Y showed equal expression levels of alloenzymes 1 and 2, respectively, which were 3 times above those of TA1538-SULT1A21. The mutagenicity of OH-AAF and OH-APP was unchanged in strain TA1538-SULT1A21Z versus 1, and moderately increased in TA1538-SULT1A22Y versus 2. The influence of the protein level was stronger with 1-HMP. Nevertheless, mutagenic activity of 1-HMP was still 11 times higher in TA1538-SULT1A21Z than in TA1538-SULT1A22Y. Thus, differences in the properties between alloenzymes can lead to differences in the activation of promutagens. The model compounds were also tested in strains expressing the other ten human SULTs identified. Whereas OH-AAF and OH-APP showed the highest mutagenic activities in strains expressing SULT1A2, 1-HMP was more potent in strains expressing other SULT forms. With the limitation that little is known about the tissue distribution and regulation of SULT1A2, the findings suggest that its polymorphism may affect the individual susceptibility towards procarcinogens, in particular certain aromatic amines and amides.
各种酶促形成的硫酸酯具有化学反应性和致突变性。在标准的体外致突变性测试系统中未检测到这种代谢活化途径。我们描述了表达人磺基转移酶1A2（SULT1A2）同工酶1、2、3、5、6的鼠伤寒沙门氏菌TA1538衍生菌株的构建。参考化合物1-羟甲基芘（1-HMP）、N-羟基-2-乙酰氨基芴（OH-AAF）和2-羟基氨基-5-苯基吡啶（OH-APP）在这些菌株中被活化为诱变剂。表达不同同工酶的菌株之间它们的活性相差7至16倍。在表达常见同工酶1和2的菌株中，其活性分别最强和最弱。在TA1538-SULT1A21和2菌株的胞质制剂中，SULT1A2蛋白表达水平以及与参考底物4-硝基苯酚的V(max)和K(m)值分别变化了2.5倍、4倍和110倍。通过在cDNA的5'部分插入沉默突变构建了具有不同蛋白水平的菌株。TA1538-SULT1A21Z和TA1538-SULT1A22Y分别显示同工酶1和2的表达水平相等，比TA1538-SULT1A21高3倍。与1相比，OH-AAF和OH-APP在TA1538-SULT1A21Z菌株中的致突变性未改变，与2相比，在TA1538-SULT1A22Y菌株中适度增加。1-HMP对蛋白水平的影响更强。然而，1-HMP在TA1538-SULT1A21Z中的诱变活性仍比TA1538-SULT1A22Y高11倍。因此，同工酶之间性质的差异可导致前诱变剂活化的差异。还在表达其他十种已鉴定的人SULTs的菌株中测试了模型化合物。虽然OH-AAF和OH-APP在表达SULT1A2的菌株中显示出最高的诱变活性，但1-HMP在表达其他SULT形式的菌株中更有效。鉴于对SULT1A2的组织分布和调控了解甚少，这些发现表明其多态性可能影响个体对致癌物前体的易感性，特别是某些芳香胺和酰胺。
