As the only enzyme of the cycle located on the outer surface of plasma membrane, gamma-glutamyl transpeptidase (GGT) plays key roles in GSH homeostasis by breaking down extracellular GSH and providing cysteine, the rate-limiting substrate, for intracellular de novo synthesis of GSH.

2009年1月1日 · In the mammalian γ-glutamyl cycle, γ-glutamyl transpeptidase (GGT) is responsible for extracellular glutathione (GSH) degradation leading to the subsequent reabsorption of the constituent amino acids into the cell. The physiological functions of the plant GGTs have recently been discovered in Arabidopsis thaliana.

2007年7月10日 · GGT4 gene expression in leaves under conditions of high demand for GSH as assayed by RT-PCR. Leaves of 30 d old plants were infiltrated with 300 μM MBB for 15 min and 100 mg of infiltrated tissue was assayed for GGT4 expression at indicated times.

2010年11月19日 · γ-Glutamyl transpeptidases (GGT) can break the γ-glutamyl bond of GSH. Previously, we found that GGT4 in Arabidopsis is responsible for degradation of GSH conjugates in the vacuole (Ohkama-Ohtsu et al. 2007), and this was confirmed by Grzam et al. (2007).

2019年12月5日 · GGT activity was positively correlated with GSH levels in the total patients and healthy controls (p<0.001 and p<0.05, respectively). There was also a positive correlation between GGT activity and GSH levels in Luminal A, HER2-positive (Human epidermal growth factor receptor 2), and Triple-negative groups (p<0.05).

Kinetics analysis suggests that γ -glutamyl cyclotransferase is the major source of GSH degradation and 5OP formation in Arabidopsis. This discovery led us to propose a new pathway for GSH turnover in plants where GSH is converted to 5OP and then to Glu by the combined action of γ -glutamyl cyclotransferase and 5-oxoprolinase in the cytoplasm.

2007年6月4日 · Detoxification of many electrophilic xenobiotics begins by reaction with reduced glutathione (GSH). Xenobiotics are covalently bound to the sulfhydryl group of GSH in a reaction catalyzed by glutathione S -transferases (GSTs) [2].

Detoxification of many electrophilic xeno-biotics begins by reaction with reduced glutathione (GSH). Xenobiotics are covalently bound to the sulfhydryl group of GSH in a reaction catalyzed by glutathione S-transferases (GSTs) [2].

2009年1月1日 · GSH degradation occurs in the cytoplasm by GGC with only minor GGT involvement in total GSH turnover. The role of the GGTs is limited to the extracytosolic space, the degradation of oxidized glutathione (GSSG) by GGT1 in the apoplast, and the metabolism of GSH conjugates by GGT4 in the vacuole.

2007年8月1日 · The GGT4-encoded isoform is present in the vacuole where it supports detoxification processes by initiating degradation of GSH conjugates formed by glutathione S-transferase following exposure...