Effects of menadione and hydrogen peroxide on glutathione status in growing Escherichia coli

详细信息    查看全文

• 作者：Smirnova ; Galina V. ; Muzyka ; Nadezda G. ; Glukhovchenko ; Marina N. ; Oktyabrsky ; Oleg N.
• 关键词：Escherichia coli ; Glutathione ; Menadione ; Hydrogen peroxide ; Free radical ; soxR and oxyR ; in italic (soxR and oxyR) when designated as a gene ; OxyR and SoxR when designated as protein product. ; CDNB ; 1-chloro-2 ; 4-dinitrobenzene ; EDTA ; ethylenediaminetetra
• 刊名：Free Radical Biology and Medicine
• 出版年：2000
• 出版时间：April, 2000
• 年：2000
• 卷：28
• 期：7
• 页码：1009-1016
• 全文大小：187 K

文摘

Menadione (MD) and H₂O₂ caused distinct effects on glutathione status in growing Escherichia coli. Treatment of E. coli AB1157 with 1–25 mM H₂O₂ did not result in an appreciable decrease in intracellular total glutathione (reduced glutathione [GSH] + oxidized glutathione [GSSG]). Only when cells were treated with 25 mM H₂O₂ an increase in GSSG and a decrease in the GSH:GSSG ratio were observed. In cells deficient in catalase HPI, such effect was observed even at 10 mM H₂O₂. The exposure of E. coli AB1157 to MD caused a dose-dependent decrease in intracellular total glutathione, an increase in GSSG, and a decrease in the ratio of GSH:GSSG. In E. coli deficient in cytosolic superoxide dismutase activity, a decrease in total glutathione after incubation with 0.2 mM MD was not accompanied by an increase in GSSG_in, and the ratio of GSH_in:GSSG_in was three times higher than in the wild-type cells. The changes in the redox status of extracellular glutathione under the action of both oxidants were similar. Although the catalase activity increased several times after exposure to both oxidants, there were little or no changes in the activity of enzymes related to glutathione metabolism. A possible role of changes in redox status of glutathione under oxidative stress is discussed.