Synthesis and initial characterization of gamma-L-glutamyl-L-thiothreonylglycine and gamma-L-glutamyl-L-allo-thiothreonylglycine as steric probes of the active site of glyoxalase I.
The diastereomeric GSH derivatives gamma-L-Glu-L-allo-thioThr-Gly (6) and gamma-L-Glu-L-thioThr-Gly (6a) have been synthesized as specific probes of the steric environment near the cysteinyl residue of enzyme bound glutathionyl substrates. Experiments with glyoxalase I indicate that while 6a-methylglyoxal thiohemiacetal is a substrate for the enzyme, 6-methylglyoxal thiohemiacetal forms a tight-binding abortive complex with the active site (Ki congruent to 100 microM). Apparently, the small size of the cysteinyl C beta-Hs proton of the normal GSH-methylglyoxal thiohemiacetal substrate for glyoxalase I is a strict requirement for productive substrate binding. These compounds may provide a novel approach to the inhibition of GSH-dependent enzymes.
Xie
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XF
Department of Chemistry and Biochemistry, University of Maryland Baltimore County 21228.
Creighton
D J
DJ
D001665:Binding Sites; D007700:Kinetics; D007791:Lactoylglutathione Lyase / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013237:Stereoisomerism; D013379:Substrate Specificity
D009842:Oligopeptides; C069047:gamma-glutamyl-thiothreonyl-glycine; D007791:Lactoylglutathione Lyase