Deuterium isotope effects on the product partitioning of fluoromethylglyoxal by glyoxalase I. Proof of a proton transfer mechanism.
Fluoromethylglyoxal in the presence of glutathione has been shown to undergo a novel glyoxalase I-catalyzed product partitioning to S-fluorolactoylglutathione and S-pyruvylglutathione with fluoride elimination. While the partition ratio (fluoride eliminated/total fluoride) was insensitive to pH 5.5-7.5 and concentrations of substrate and glyoxalase I, it was species-dependent. When [1-2H]fluoromethylglyoxal was reacted with glyoxalase I, an increase in the partition ratio and retention of deuterium in the product fluorolactate was observed. This result can only be explained by a selective primary isotope effect on the protonation of an enediol intermediate relative to fluoride elimination.
D000447:Aldehydes; D000818:Animals; D002417:Cattle; D003903:Deuterium; D006037:Glyoxal / Q000031:analogs & derivatives; D007700:Kinetics; D007791:Lactoylglutathione Lyase / Q000378:metabolism*; D008099:Liver / Q000201:enzymology; D008190:Lyases / Q000378:metabolism*; D051379:Mice; D011865:Radioisotope Dilution Technique; D051381:Rats; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D013869:Thiolester Hydrolases / Q000378:metabolism; D000099301:Hydroxyacylglutathione Hydrolase
D000447:Aldehydes; D003903:Deuterium; D006037:Glyoxal; D007791:Lactoylglutathione Lyase; D008190:Lyases; D013869:Thiolester Hydrolases; D000099301:Hydroxyacylglutathione Hydrolase; C032101:fluoromethylglyoxal