Methylglyoxal detoxification in plants: Role of glyoxalase pathway

Abstract

Methylglyoxal (MG) is a potent cytotoxin being produced primarily as result of non-enzymatic reactions in the living systems. The toxicity of MG is believed to be due to its ability to carry out glycation of proteins, nucleic acids and phospholipids. MG can readily modify proteins and nucleic acids, forming advanced glycation end-products which results in cellular dysfunction. In order to limit MG levels, several detoxification enzymes exist in the living systems which can metabolize MG. Of these, glyoxalase pathway is considered to be the primary route of MG metabolism. Here, we have discussed the effects of MG on the functioning of different subcellular compartments and the detoxification machineries existing in these organelles to counter excess MG. We describe how MG exerts its toxic effects at the cellular level and how the cell defends itself from MG. In this context, we have highlighted the important role of glyoxalase pathway in plants. Further, we have also discussed how glycolytic products and enzymes control MG levels and how MG regulates the activity of these glycolytic products as a part of substrate and end-product regulatory mechanisms. Overall, we present a comprehensive overview of MG toxicity and detoxification in the cell and its regulation.