Hiratsuka A, Sebata N, Kawashima K, Okuda H, Ogura K, Watabe T, Satoh K, Hatayama I, Tsuchida S, Ishikawa T
Department of Hygienic Chemistry, Tokyo College of Pharmacy, Japan.
J Biol Chem. 1990 Jul 15;265(20):11973-81.
A glutathione (GSH) S-transferase (GST), catalyzing the inactivation of reactive sulfate esters as metabolites of carcinogenic arylmethanols, was isolated from the male Sprague-Dawley rat liver cytosol and purified to homogeneity in 12% yield with a purification factor of 901-fold. The purified GST was a homo-dimeric enzyme protein with subunit Mr 26,000 and pI 7.9 and designated as Yrs-Yrs because of its enzyme activity toward "reactive sulfate esters." GST Yrs-Yrs could neither be retained on the S-hexylglutathione gel column nor showed any activity toward 1,2-dichloro-4-nitrobenzene, 4-nitrobenzyl chloride, and 1,2-epoxy-3-(4'-nitrophenoxy)propane. 1-Chloro-2,4-dinitro-benzene was a very poor substrate for this GST. 1-Menaphthyl sulfate was the best substrate for GST Yrs-Yrs among the examined mutagenic arylmethyl sulfates. The enzyme had higher activities toward ethacrynic acid and cumene hydroperoxide. N-terminal amino acid sequence of subunit Yrs, analyzed up to the 25th amino acid, had no homology with any of the known class alpha, mu, and pi enzymes of the Sprague-Dawley rat. Anti-Yrs-IgG raised against GST Yrs-Yrs showed no cross-reactivity with any of subunits Ya, Yc, Yb1, Yb2, and Yp. Anti-IgGs raised against Ya, Yc, Yb1, Yb2, and Yp also showed no cross-reactivity with GST Yrs-Yrs. The purified enzyme proved to differ evidently from the 12 known cytosolic GSTs in various tissues of the rat in all respects. Immunoblot analysis of various tissue cytosols of the male rat indicated that apparent concentrations of the GST Yrs-Yrs protein were in order of liver greater than testis greater than adrenal greater than kidney greater than lung greater than brain greater than skeletal muscle congruent to heart congruent to small intestine congruent to spleen congruent to skin congruent to 0.
从雄性斯普拉格 - 道利大鼠肝脏胞质溶胶中分离出一种谷胱甘肽（GSH）S - 转移酶（GST），它催化致癌芳基甲醇代谢产物活性硫酸酯的失活，并以12%的产率纯化至同质，纯化倍数为901倍。纯化后的GST是一种同二聚体酶蛋白，亚基Mr为26,000，pI为7.9，因其对“活性硫酸酯”的酶活性而被命名为Yrs - Yrs。GST Yrs - Yrs既不能保留在S - 己基谷胱甘肽凝胶柱上，对1,2 - 二氯 - 4 - 硝基苯、4 - 硝基苄基氯和1,2 - 环氧 - 3 -（4'- 硝基苯氧基）丙烷也无任何活性。1 - 氯 - 2,4 - 二硝基苯是这种GST的一种很差的底物。在所检测的诱变芳基甲基硫酸盐中，1 - 萘基硫酸盐是GST Yrs - Yrs的最佳底物。该酶对依他尼酸和氢过氧化异丙苯具有较高活性。对亚基Yrs的N端氨基酸序列分析至第25个氨基酸，与斯普拉格 - 道利大鼠已知的α、μ和π类酶均无同源性。针对GST Yrs - Yrs产生的抗Yrs - IgG与Ya、Yc、Yb1、Yb2和Yp亚基均无交叉反应。针对Ya、Yc、Yb1、Yb2和Yp产生的抗IgG与GST Yrs - Yrs也无交叉反应。纯化后的酶在各方面均明显不同于大鼠各组织中已知的12种胞质GST。对雄性大鼠各种组织胞质溶胶的免疫印迹分析表明，GST Yrs - Yrs蛋白的表观浓度顺序为肝脏＞睾丸＞肾上腺＞肾脏＞肺＞脑＞骨骼肌≈心脏≈小肠≈脾脏≈皮肤≈0。
