Absence of beta-galactosidase (lactase) activity from intestinal brush borders of suckling macropods: implications for mechanism of lactose absorption.
1. Neutral beta-galactosidase (lactase) activity was absent from crude brush borders of small intestines of three species of suckling macropods (kangaroos and wallabies), even though the intestinal mucosal homogenates had high beta-galactosidase activities. 2. These activities were entirely due to an intracellular acid beta-galactosidase, probably located in lysosomes. 3. The results suggest that the absorptive-digestive mechanism for lactose in macropods is fundamentally different from that in eutherian mammals.
D000818:Animals; D000833:Animals, Suckling; D005696:Galactosidases / Q000032:analysis*; D007408:Intestinal Absorption; D007421:Intestine, Small / Q000201:enzymology*; D007785:Lactose / Q000378:metabolism*; D007614:Macropodidae / Q000378:metabolism*; D008394:Marsupialia / Q000378:metabolism*; D008871:Microvilli / Q000201:enzymology*; D051381:Rats; D011919:Rats, Inbred Strains; D013045:Species Specificity; D001616:beta-Galactosidase / Q000032:analysis*
D005696:Galactosidases; D001616:beta-Galactosidase; D007785:Lactose