title: Some characteristics of early appearing isomaltase in intestinal mucosa of suckling rat.
abstract: Characteristics of early appearing free isomaltase in the soluble fraction were investigated in rat intestinal mucosa. Soluble isomaltase and membrane-bound sucrase-isomaltase complex were prepared from 15-day-old rat intestine. Immunochemical properties, optimal pH and heat sensitivity of soluble isomaltase were compared with those of membrane-bound isomaltase. Optimal pH of free isomaltase in the soluble fraction was lower than that of membrane-bound isomaltase. Soluble and membrane-bound isomaltase showed different sensitivities for temperature. Furthermore, membrane-bound isomaltase in 15-day-old suckling rat intestine gave a single line with antiserum. However, soluble isomaltase gave no precipitin line. From these results, it could be concluded that soluble isomaltase is not derived from the isomaltase moiety of membrane-bound sucrase-isomaltase complex as a result of mechanical fragility and rather it would be lysosomal in origin.
mesh_terms: D000818:Animals; D000833:Animals, Suckling; D005260:Female; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D005779:Immunodiffusion; D007413:Intestinal Mucosa / Q000201:enzymology* / Q000648:ultrastructure; D007425:Intracellular Membranes / Q000201:enzymology; D008871:Microvilli / Q000201:enzymology; D009097:Multienzyme Complexes / Q000378:metabolism*; D009834:Oligo-1,6-Glucosidase / Q000378:metabolism*; D011247:Pregnancy; D011485:Protein Binding; D051381:Rats; D012995:Solubility; D013394:Sucrase-Isomaltase Complex / Q000378:metabolism*
chemical_list: D009097:Multienzyme Complexes; D006026:Glycoside Hydrolases; D013394:Sucrase-Isomaltase Complex; D009834:Oligo-1,6-Glucosidase