In Escherichia coli, detoxification of methylglyoxal (MG) requires glyoxalases I and II. Glyoxalase I (gloA/GlxI) isomerizes the hemithioacetal, formed spontaneously from MG and glutathione (GSH) to S-lactoylglutathione (SLG), which is hydrolyzed by glyoxalase II (gloB/GlxII) to lactate and GSH. YcbL from Salmonella enterica serovar Typhimurium is an unusual type II glyoxalase whose role in MG detoxification has remained enigmatic. Here we show that YcbL (gloC/GlxII-2) acts as an accessory type II glyoxylase in E. coli. The two isoenzymes have additive effects and ensure maximal MG degradation.
在大肠杆菌中,
甲基乙二醛(MG)的解毒需要
乙二醛酶I和II。
乙二醛酶I(gloA/GlxI)将半
硫代
缩醛(由MG和
谷胱甘肽(GSH)自发形成)异构化为
S-乳酰谷胱甘肽(SLG),后者由
乙二醛酶II(gloB/GlxII)
水解为
乳酸和GSH。肠炎沙门氏菌(Salmonella enterica serovar Typhimurium)的YcbL是一种不寻常的II型
乙二醛酶,其在MG解毒中的作用一直是个谜。在这里,我们展示了YcbL(gloC/GlxII-2)在大肠杆菌中作为辅助II型
乙二醛酶的作用。这两种同工酶具有协同作用,可确保最大程度的MG降解。