Enzymatic Activity of “High‐Mannose” Glycosylated Forms of Intestinal Microvillar Hydrolases

Abstract

The “high‐mannose” glycosylated forms of aminopeptidase N (EC 3.4.11.2), maltase‐glucoamylase (EC 3.2.1.20), and sucrase‐isomaltase (EC 3.2.1.48, EC 3.2.1.10) have been purified. The high‐mannose glycosylated form of sucrase‐isomaltase was found to have a lower specific activity than the complex glycosylated form, whereas no difference was observed for the two other enzymes. The change in glycosylation from high‐mannose to complex form thus seems to be of importance for the enzymatic activity of sucrase‐isomaltase either by direct structural involvement or by a general stabilization effect on the protein conformation.