The unique feature of dog liver cytosolic glutathione S-transferases. An isozyme not retained on the affinity column has the highest activity toward 1,2-dichloro-4-nitrobenzene.
The unique feature of dog liver cytosolic glutathione S-transferases. An isozyme not retained on the affinity column has the highest activity toward 1,2-dichloro-4-nitrobenzene.
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狗肝细胞质谷胱甘肽S-转移酶的独特功能。
DOI：
10.1016/s0021-9258(18)54694-9
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
T. Satoh
中科院分区：
文献类型：
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作者：
T. Igarashi;A. Kohara;Y. Shikata;F. Sagami;J. Sonoda;T. Horie;T. Satoh
在成年犬肝细胞浆中，我们鉴定了四个谷胱甘肽S转移酶(GST)亚基，Yd1(Mr 26,000)、YD2(Mr 27,000)、Yd3(Mr 28,000)和Ydf(Mr 27,400)，并纯化了由Yd1、Yd2和Yd3组成的GST形式，显示出明显的同质性。与大鼠转移酶不同，亲和层析柱上不保留对1，2-二氯-4-硝基苯(DCNB)的酶活性。因此，通过凝胶过滤、DE52层析、层析聚焦和羟基磷灰石柱层析，从亲和层析的流过部分中也纯化了DCNB活性酶GST YdfYdf。对犬GSTs的免疫印迹分析表明，Yd1、Yd2和Yd3亚基分别属于pi、α和u类。相反，YDF对三类GST中的任何一种都没有反应活性。每个亚基Yd1、Yd2、Yd3和Ydf在反相高效液相色谱上的保留时间可以区分开来。犬GSTS Yd1Yd1和Yd3Yd3的N端氨基酸序列分别与大鼠、人和小鼠的pI和Mu类转移酶高度同源，而Yd2Yd2的N端被阻断。GST YdfYdf的N端氨基酸序列与三类GST中的任何一类都没有同源性。GST YdfYdf注意到的最重要的性质是对DCNB的高比活性，超过已知Mu类GST的相应值1个数量级。这些结果有力地表明，狗的GST YdfYdf是一种独特的酶，不同于迄今所描述的GST同工酶。
In the adult dog liver cytosol we identified four glutathione S-transferase (GST) subunits, Yd1 (Mr 26,000), Yd2 (Mr 27,000), Yd3 (Mr 28,000), and Ydf (Mr 27,400), and purified GST forms comprising Yd1, Yd2, and Yd3, to apparent homogeneity. Unlike rat transferases the enzyme activity toward 1,2-dichloro-4-nitrobenzene (DCNB) was not retained on the affinity column. Thus the DCNB-active enzyme, GST YdfYdf, from the flow-through fraction of the affinity column was also purified to homogeneity by gel filtration, DE52 chromatography, chromatofocusing, and hydroxylapatite column chromatography. Immunoblot analysis of dog GSTs revealed that the subunits Yd1, Yd2, and Yd3 belong to the pi, alpha, and mu class, respectively. On the contrary, Ydf had no reactivity with antibodies raised against any of the three classes of GST. Each subunit, Yd1, Yd2, Yd3, and Ydf, was distinguishable by its own retention time on reverse-phase high performance liquid chromatography. N-terminal amino acid sequences of the dog GSTS Yd1Yd1 and Yd3Yd3 revealed a high degree of homology to the pi and mu class transferases from rat, human, and mouse, respectively, while the N terminus of Yd2Yd2 is blocked. N-terminal amino acid sequences of GST YdfYdf showed no homology to any of the three classes of GST. The most significant property noted of GST YdfYdf is the high specific activity toward DCNB, exceeding by 1 order of magnitude the corresponding values for the known mu class GSTs. The present results strongly suggest that dog GST YdfYdf is a unique enzyme distinct from the hitherto characterized GST isozymes.