Glactoyl-glutathione lyase (or glyoxalase I) is part of the glyoxalase system which catalyses the conversion of acyclic alpha-oxoaldehydes into the corresponding alpha-hydroxyacids. Glyoxalase I catalyses the isomerization of the hemithioacetal (formed spontaneously from alpha-oxoaldehyde and GSH), to S-2-hydroxyacylglutathione (or R) derivatives, therefore decreasing the steady-state concentrations of physiological alpha-oxoaldehydes and associated glycation reactions. Physiological substrates of glyoxalase I are methylglyoxal, glyoxal and other acyclic alpha-oxoaldehydes. This is the first of two steps in the conversion of 2-oxo-aldehydes to the corresponding 2-hydroxycarboxylic acids by way of the glyoxylase system. Methylglyoxal is produced as a by product of the triosephosphate isomerase reaction in glycolysis and, if not removed, is toxic as it reacts readily with with proteins and nucleic acids.
Defined by 4 residues: HIS:A-74GLU:A-122HIS:B-5GLU:B-56