A continuous automated method for the determination of intestinal disaccharidase activities

A reliable method for the measurement of various disaccharidase activities such as maltase, isomaltase and sucrase is introduced. It is based on the continuous measurement of liberated glucose by a commercially available glucose dehydrogenase reagent. The procedures were first optimized for enzymes from rat intestinal mucosa. The pH optima were similar (6.3-6.7) for the three enzymes tested, and the apparent Kms were estimated to be 18, 12 and 19 mmol/l for maltase, isomaltase and sucrase, respectively. The procedures were adapted on a Cobas Mira automated analyzer. The assays correlated strongly with the conventional method of Dahlqvist. They were reliable, rapid, easy to perform and validate because the progress curve of each reaction rate can be continuously monitored. The method described has also been applied to human intestinal mucosa (Caco-2 cells).