Glyoxalase substrate specificity

But we can assign to GSH more specific functions also. It participates in transpeptidations and oxidation reductions as well as in hydration-dehydration reactions. Perhaps this large variety of reactions has more in common than appears at first sight. Many of the transpeptidation reactions have been shown to occur with enzymes such as the cathepsins which require SH groups for activity. Hydrolysis of thiol esters by papain has been recently demonstrated (66) and the formation of thiol esters as intermediates in transpeptidations still remains to be explored. In the glyoxalase reaction the actual substrate may be the hydrated form of the aldehyde, in which case the reaction mechanism would be one of dehydration and hydrolysis rather than of a hydrogen shift. Thus the reaction will bear some similarity to the aconitase reaction which is stimulated by SH compounds and ferrous ions (67). 

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