Song Seung-Hyun, Lim Chang-Jin
Division of Life Sciences and Research Institute of Life Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea.
J Microbiol. 2008 Feb;46(1):70-4. doi: 10.1007/s12275-007-0244-y.
This work aims to elucidate the relationship between nitrogen depletion and Glutathione (GSH) level in Schizosaccharomyces pombe. The total GSH level was much higher in the Pap1-positive KP1 cells than in the Pap1-negative TP108-3C cells, suggesting that synthesis of GSH is dependent on Pap1. When the Pap1-positive KP1 cells were transferred to the nitrogen-depleted medium, total GSH level significantly increased up to 6 h and then slightly declined after 9 h. Elevation of the total GSH level was observed to be much less with the Pap1-negative cells. However, glucose deprivation was not able to enhance the GSH level in the KP1 cells. Activity of gamma-glutamyltranspeptidase (gamma-GT), an enzyme in the first step of GSH catabolism, also increased during nitrogen depletion. The total GSH level was more significantly enhanced in the KP1 cells overexpressing gamma-GT2 than gamma-GT1 during nitrogen starvation. Reactive oxygen species (ROS) levels were not changed during nitrogen starvation in both Pap1-positive and Pap1-negative cells. Collectively, nitrogen depletion causes up-regulation of GSH synthesis and gamma-GT in a Pap1-dependent manner.
这项工作旨在阐明粟酒裂殖酵母中氮消耗与谷胱甘肽（GSH）水平之间的关系。Pap1阳性的KP1细胞中的总GSH水平远高于Pap1阴性的TP108-3C细胞，这表明GSH的合成依赖于Pap1。当Pap1阳性的KP1细胞转移到氮耗尽的培养基中时，总GSH水平在6小时内显著增加，然后在9小时后略有下降。在Pap1阴性细胞中，总GSH水平的升高要少得多。然而，葡萄糖剥夺并不能提高KP1细胞中的GSH水平。γ-谷氨酰转肽酶（γ-GT）是GSH分解代谢第一步中的一种酶，其活性在氮消耗期间也会增加。在氮饥饿期间，过表达γ-GT2的KP1细胞中的总GSH水平比过表达γ-GT1的细胞更显著地升高。在Pap1阳性和Pap1阴性细胞的氮饥饿期间，活性氧（ROS）水平均未发生变化。总的来说，氮消耗以Pap1依赖的方式导致GSH合成和γ-GT的上调。
