Glyoxal detoxification in Escherichia coli K-12 by NADPH dependent aldo-keto reductases.

Glyoxal (GO) and methylglyoxal (MG) are reactive carbonyl compounds that are accumulated in vivo through various pathways. They are presumably detoxified through multiple pathways including glutathione (GSH)-dependent/independent glyoxalase systems and NAD(P)H dependent reductases. Previously, we reported an involvement of aldo-ketoreductases (AKRs) in MG detoxification. Here, we investigated the role of various AKRs (YqhE, YafB, YghZ, YeaE, and YajO) in GO metabolism. Enzyme activities of the AKRs to GO were measured, and GO sensitivities of the corresponding mutants were compared. In addition, we examined inductions of the AKR genes by GO. The results indicate that AKRs efficiently detoxify GO, among which YafB, YghZ, and YeaE are major players.