Sucrase-isomaltase and cystic fibrosis.
The intestinal microvillar enzyme complex sucrase-isomaltase has been studied in cystic fibrosis and control ileum. A number of biochemical parameters of the enzyme in ileum homogenates have been determined. Both solubilized as well as membrane-bound sucrase-isomaltase were analyzed with respect to their reaction with monoclonal antibodies against human sucrase-isomaltase. Finally the subcellular localization of sucrase-isomaltase was verified by immunoelectronmicroscopy or via the analysis of purified brush-border membrane preparations. At all levels no significant differences could be detected between sucrase-isomaltase of cystic fibrosis and control ileum. It is concluded that an abnormal subcellular localization and/or abnormal enzymatic activity of sucrase-isomaltase in cystic fibrosis intestine cannot explain the markedly decreased disaccharidase activities in amniotic fluids from pregnancies resulting in a child affected with cystic fibrosis.
D000911:Antibodies, Monoclonal; D003550:Cystic Fibrosis / Q000201:enzymology*; D000939:Epitopes / Q000032:analysis; D006056:Golgi Apparatus / Q000201:enzymology; D006801:Humans; D007082:Ileum / Q000201:enzymology* / Q000648:ultrastructure; D007223:Infant; D008871:Microvilli / Q000201:enzymology; D009097:Multienzyme Complexes / Q000378:metabolism*; D013394:Sucrase-Isomaltase Complex / Q000032:analysis / Q000276:immunology / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D009097:Multienzyme Complexes; D013394:Sucrase-Isomaltase Complex