Glycolytic-methylglyoxal pathway -: Molecular evolution and stress response of glyoxalase I in Saccharomyces cerevisiae

Methylglyoxal is an endogenous cytotoxic compound formed as a byproduct of glycolysis. We systematically analyzed the metabolic fate of methylglyoxal in various microorganisms and found that glyoxalase I is a ubiquitous and critical enzyme for its detoxification. We found that glyoxalase I consists of five segments (regions I-V) which are conserved among the glyoxalase Is of various species. We hypothesize that yeast glyoxalase I evolved by gene duplication and here show supporting evidence. We also found that expression of the structural gene for the glyoxalase I of S. cerevisiae is induced by osmotic stress through the HOG-MAG kinase signaling pathway. We identified the physiological significance of this glycolytic-methylglyoxal pathway in S, cerevisiae.