Interaction of L-gamma-glutamyl-alpha,beta-dehydroamino acids with gamma-glutamyl transpeptidase

Three gamma -glutamyl alpha,beta -dehydroamino acids: L-gamma -glutamyl-deh ydroalanine, L-gamma -glutamyl-(Z)-dehydrobutyrine and L-gamma -glutamyl-(E )-dehydrobutyrine have been prepared as potential ligands (inhibitors or su bstrates) for gamma -glutamyl transpeptidase (GGT). Both isomers of gamma - glutamyl-dehydrobutyrines proved to be inhibitors of GGT, slightly better t han the saturated analogue, L-gamma -glutamyl-L-butyrine. However, their so lvolysis catalysed by the enzyme is slower than that of the latter. L-gamma -Glutamyl-(E)-dehydrobutyrine seems to be a more active compound in both e nzymatic tests. L-gamma -Glutamyl-dehydroalanine elicited only low inhibito ry activity and, moreover, was unstable under conditions of the solvolysis test.