The influence of Amadori-compounds (fructosyl-, maltulosyl- and maltotriulosylglycin) on the activity of the enzymes alpha-glucosidase (from Saccharomyces cerevisiae), glucoamylase (from Aspergillus niger) and alpha-amylase (from porcine pancreas) was studied. Fructosylglycin was not hydrolyzed by all three enzymes. alpha-Glucosidase hydrolyzes maltulosylglycin 10 times slower than maltotriulosylglycin. Glucoamylase and alpha-amylase catalyze only the cleavage of maltotriulosylglycin to form glucose and maltulosylglycin. The activities of alpha-glucosidase and glucoamylase are inhibited through the Amadori-compounds fructosyl- and maltulosylglycin. These Amadori-compounds don't influence the activity of alpha-amylase. Electronic effects or interactions between the secondary amino function of Amadori-compounds and the carboxyl- or carboxylate groups of active centres could be responsible for such an inhibition.