Human glutathione S-transferases. Characterization of the anionic forms from lung and placenta.
Human glutathione S-transferases. Characterization of the anionic forms from lung and placenta.
复制标题
人谷胱甘肽 S-转移酶。
DOI：
10.1042/bj2210033
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Awasthi,YC
中科院分区：
文献类型：
--
作者：
Dao,DD;Partridge,CA;Kurosky,A;Awasthi,YC
从人肺和胎盘中提纯了阴离子谷胱甘肽S转移酶。化学和免疫化学特征，包括聚丙烯酰胺凝胶电泳，提供了强有力的证据表明，阴离子肺和胎盘酶在化学上相似，如果不是相同的，蛋白质。这两种蛋白质在常规碱性凝胶和含有十二烷基硫酸钠的凝胶中的电泳率是相同的。对完整的活性酶进行凝胶过滤，测得其相对分子质量为45000，而十二烷基硫酸钠/聚丙烯酰胺凝胶电泳法在解离条件下测得亚基的相对分子质量为22500。对胎盘酶N-末端的氨基酸序列分析表明，有一个与肺相同的多肽序列。免疫电泳法、免疫滴定法、双向免疫扩散法和火箭免疫电泳法的结果也表明，阴离子肺和胎盘酶非常相似。蛋白质组成分析和化学水解后的片段分析进一步支持了这两种蛋白质的化学相似性。肺和胎盘阴离子酶与人肝谷胱甘肽S转移酶的免疫化学比较显示，与阴离子omega酶有交叉反应，但与阳离子酶无交叉反应。将人阴离子酶的N末端序列与已报道的大鼠肝脏谷胱甘肽S转移酶序列进行比较，得到了化学相似性的有力证据，表明这些酶在进化上是相关的。然而，对30个残基的N末端序列的计算机分析没有显示出与任何其他已报道的蛋白质序列有任何显著的化学相似性，这表明谷胱甘肽S转移酶代表了一类独特的蛋白质。
Anionic glutathione S-transferases were purified from human lung and placenta. Chemical and immunochemical characterization, including polyacrylamide-gel electrophoresis, gave strong evidence that the anionic lung and placental enzymes are chemically similar, if not identical, proteins. The electrophoretic mobilities of both proteins were identical in conventional alkaline gels as well as in gels containing sodium dodecyl sulphate. Gel filtration of the intact active enzyme established an Mr value of 45000; however, with sodium dodecyl sulphate/polyacrylamide-gel electrophoresis under dissociating conditions a subunit Mr of 22500 was obtained. Amino acid sequence analysis of the N-terminal region of the placental enzyme revealed a single polypeptide sequence identical with that of lung. Results obtained from immunoelectrophoresis, immunotitration, double immunodiffusion and rocket immunoelectrophoresis also indicated the anionic lung and placental enzymes to be closely similar. The chemical similarity of these two proteins was further supported by protein compositional analysis and fragment analysis after chemical hydrolysis. Immunochemical comparison of the anionic lung and placental enzymes with human liver glutathione S-transferases revealed cross-reactivity with the anionic omega enzyme, but no cross-reactivity was detectable with the cationic enzymes. Comparison of the N-terminal region of the human anionic enzyme with reported sequences of rat liver glutathione S-transferases gave strong evidence of chemical similarity, indicating that these enzymes are evolutionarily related. However, computer analysis of the 30-residue N-terminal sequence did not show any significant chemical similarity to any other reported protein sequence, pointing to the fact that the glutathione S-transferases represent a unique class of proteins.