Awasthi Y C, Dao D D, Saneto R P
Biochem J. 1980 Oct 1;191(1):1-10. doi: 10.1042/bj1910001.
Human liver glutathione S-transferases (GSH S-transferases) were fractionated into cationic and anionic proteins. During fractionation with (NH4)2SO4 the anionic GSH S-transferases are concentrated in the 65%-saturated-(NH4)2SO4 fraction, whereas the cationic GSH S-transferases separate in the 80%-saturated-(NH4)2SO4 fraction. From the 65%-saturated-(NH4)2SO4 fraction two new anionic GSH S-transferases, omega and psi, were purified to homogeneity by using ion-exchange chromatography on DEAE-cellulose, Sephadex G-200 gel filtration, affinity chromatography on GSH bound to epoxy-activated Sepharose and isoelectric focusing. By a similar procedure, cationic GSH S-transferases were purified from the 80%-saturated-(NH4)2SO4 fraction. Isoelectric points of GSH S-transferases omega and psi are 4.6 and 5.4 respectively. GSH S-transferase omega is the major anionic GSH S-transferase of human liver, whereas GSH S-transferase psi is present only in traces. The subunit mol.wt. of GSH S-transferase omega is about 22500, whereas that of cationic GSH S-transferases is about 24500. Kinetic and structural properties as well as the amino acid composition of GSH S-transferase omega are described. The antibodies raised against cationic GSH S-transferases cross-react with GSH S-transferase omega. There are significant differences between the catalytic properties of GSH S-transferase omega and the cationic GSH S-transferases. GSH peroxidase II activity is displayed by all five cationic GSH S-transferases, whereas both anionic GSH S-transferases do not display this activity.
人肝谷胱甘肽S-转移酶（GSH S-转移酶）被分离为阳离子蛋白和阴离子蛋白。在用硫酸铵分级分离过程中，阴离子GSH S-转移酶集中在65%饱和度的硫酸铵级分中，而阳离子GSH S-转移酶则在80%饱和度的硫酸铵级分中分离出来。从65%饱和度的硫酸铵级分中，通过在DEAE-纤维素上进行离子交换色谱、Sephadex G-200凝胶过滤、在与环氧活化琼脂糖结合的谷胱甘肽上进行亲和色谱以及等电聚焦，纯化出两种新的阴离子GSH S-转移酶，即ω和ψ，使其达到均一性。通过类似的程序，从80%饱和度的硫酸铵级分中纯化出阳离子GSH S-转移酶。GSH S-转移酶ω和ψ的等电点分别为4.6和5.4。GSH S-转移酶ω是人肝中主要的阴离子GSH S-转移酶，而GSH S-转移酶ψ仅微量存在。GSH S-转移酶ω的亚基分子量约为22500，而阳离子GSH S-转移酶的亚基分子量约为24500。描述了GSH S-转移酶ω的动力学和结构特性以及氨基酸组成。针对阳离子GSH S-转移酶产生的抗体与GSH S-转移酶ω发生交叉反应。GSH S-转移酶ω和阳离子GSH S-转移酶的催化特性存在显著差异。所有五种阳离子GSH S-转移酶都表现出谷胱甘肽过氧化物酶II活性，而两种阴离子GSH S-转移酶都不表现出这种活性。
