Choi J H, Lou W, Vancura A
Department of Biological Sciences, St. John's University, Jamaica, New York 11439, USA.
J Biol Chem. 1998 Nov 6;273(45):29915-22. doi: 10.1074/jbc.273.45.29915.
The glutathione S-transferases (GSTs) represent a significant group of detoxification enzymes that play an important role in drug resistance in all eukaryotic species. In this paper we report an identification and characterization of the two Saccharomyces cerevisiae genes, GTT1 and GTT2 (glutathione transferase 1 and 2), coding for functional GST enzymes. Despite only limited similarity with GSTs from other organisms (approximately 50%), recombinant Gtt1p and Gtt2p exhibit GST activity with 1-chloro-2, 4-dinitrobenzene as a substrate. Both Gtt1p and Gtt2p are able to form homodimers, as determined by two hybrid assay. Subcellular fractionation demonstrated that Gtt1p associates with the endoplasmic reticulum. Expression of GTT1 is induced after diauxic shift and remains high throughout the stationary phase. Strains deleted for GTT1 and/or GTT2 are viable but exhibit increased sensitivity to heat shock in stationary phase and limited ability to grow at 39 degreesC.
谷胱甘肽S-转移酶（GSTs）是一类重要的解毒酶，在所有真核生物的耐药性中发挥着重要作用。在本文中，我们报告了酿酒酵母中两个编码功能性GST酶的基因GTT1和GTT2（谷胱甘肽转移酶1和2）的鉴定和特征。尽管与其他生物的GSTs只有有限的相似性（约50%），但重组Gtt1p和Gtt2p以1-氯-2,4-二硝基苯为底物表现出GST活性。通过双杂交试验确定，Gtt1p和Gtt2p都能够形成同型二聚体。亚细胞分级分离表明，Gtt1p与内质网相关。GTT1的表达在二次生长转换后被诱导，并在整个稳定期保持高水平。缺失GTT1和/或GTT2的菌株是可行的，但在稳定期对热休克表现出更高的敏感性，并且在39℃下生长的能力有限。
