HUMAN INTESTINAL DISACCHARIDASES AND HEREDITARY DISACCHARIDE INTOLERANCE. THE HYDROLYSIS OF SUCROSE, ISOMALTOSE, PALATINOSE (ISOMALTULOSE), AND A 1,6-α-OLIGOSACCHARIDE (ISOMALTO-OLIGOSACCHARIDE) PREPARATION*

Abstract

The specificity of the human small intestinal enzymes hydrolyzing isomaltose, sucrose, palatinose (isomaltulose) and a 1,6-[alpha]-oligosaccharide (isomalto-oligosaccharide) preparation have been studied with heat inactivation and mixed-substrate incubation experiments. The isomaltase and invertase activities are independent of each other as shown by these methods. Isomaltase is responsible for the hydrolysis of both palatinose and the 1,6-[alpha]-oligosaccharide preparation. The use of these for clinical tolerance tests to reveal intestinal isomaltase deficiency thus is justified. The clinical investigations hitherto made indicate that hereditary intolerance for sucrose and isomaltose often, and possibly always, follow each other. These patients may lack two enzymes, which is remarkable in view of previous knowledge of inborn errors of metabolism.