Wijffels G L, Sexton J L, Salvatore L, Pettitt J M, Humphris D C, Panaccio M, Spithill T W
Victorian Institute of Animal Science, Department of Agriculture, Attwood, Australia.
Exp Parasitol. 1992 Feb;74(1):87-99. doi: 10.1016/0014-4894(92)90142-w.
Glutathione S-transferases (GSTs) from Fasciola hepatica have been purified by glutathione affinity chromatography. Two closely migrating species of Mr 26,000 and 26,500 were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and several species resolved by two-dimensional gel analysis, indicating substantial heterogeneity among the GSTs. N-terminal amino acid sequencing revealed one core sequence containing three polymorphisms, whereas the sequence of GST peptides implied a minimum of three different GSTs. The amino acid sequence data assigned the F. hepatica GSTs to the mu class of GSTs with high similarities to these proteins in other helminths and mammals. The native GSTs of F. hepatica appeared to behave as dimers as determined by molecular sieving chromatography. The observation that the GSTs of F. hepatica are heterogeneous in sequence and behave as dimers in the native state suggest that these isoenzymes may exhibit considerable functional heterogeneity which may be of importance to the parasite. Immunocytochemical studies suggest that the main source of GST in F. hepatica are the parenchymal cells and peripheral tissues of the parasite. Some extracellular GST is associated with the lamellae of the intestinal epithelium. The identification of an intestinal GST is unique among trematodes studied to date.
通过谷胱甘肽亲和层析法纯化了肝片吸虫的谷胱甘肽S-转移酶（GSTs）。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳鉴定出两种迁移相近、分子量分别为26,000和26,500的蛋白条带，二维凝胶分析解析出了几种不同的蛋白条带，这表明GSTs之间存在显著的异质性。N端氨基酸测序揭示了一个包含三种多态性的核心序列，而GST肽段的序列表明至少存在三种不同的GST。氨基酸序列数据将肝片吸虫的GSTs归为GSTs的μ类，与其他蠕虫和哺乳动物中的这些蛋白具有高度相似性。通过分子筛层析确定，肝片吸虫的天然GSTs表现为二聚体。肝片吸虫的GSTs在序列上具有异质性且在天然状态下表现为二聚体，这一观察结果表明这些同工酶可能表现出相当大的功能异质性，这可能对寄生虫很重要。免疫细胞化学研究表明，肝片吸虫中GST的主要来源是寄生虫的实质细胞和外周组织。一些细胞外GST与肠上皮的薄片相关。肠GST的鉴定在迄今为止研究的吸虫中是独一无二的。
