title: Characteristics of human intestinal acid sialidase.
abstract: With methylumbelliferyl-N-acetyl-neuraminic acid (MU-NANA) as substrate, acid sialidase was determined in intestinal biopsies of children. The enzyme has an acid pH optimum, a Km value of 4 mmol/l and a pronounced thermal lability which can be partially prevented by the addition of albumin. N-acetyl-neuraminic acid (NANA) and derivatives as well as other glycoprotein and oligosaccharide sialidase substrates inhibit sialidase whereas gangliosides have no effect. This could be an indication that intestinal MU-NANA sialidase is different from ganglioside sialidase as has been reported for many other tissues.
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006923:Hymecromone / Q000031:analogs & derivatives; D007223:Infant; D007421:Intestine, Small / Q000201:enzymology*; D019158:N-Acetylneuraminic Acid; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012794:Sialic Acids / Q000494:pharmacology; D013379:Substrate Specificity
chemical_list: D012794:Sialic Acids; D006923:Hymecromone; C021224:2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid