title: Methylumbelliferyl-N-acetyl-neuraminic acid (MU-NANA) sialidase in human fibroblasts. Further characterization of the enzyme.
abstract: The enzyme properties of acid sialidase have been investigated in cultured fibroblasts. An extended period of homogenization at 0 degree C, did only minimally inactivate the enzyme and 90% and 80% of the activity was recovered after 3 and 5 minutes of homogenization respectively. Bovine serum albumin is an affective protector of the enzyme. The activity of the enzyme was 70% and 18% respectively at 23 degrees C and 0 degree C, in comparison with the activity measured at 37 degrees C. 55% of the sialidase activity was recovered after a homogenate had been kept frozen for 6 months at--20 degrees C. Methoxyphenyl-sialic acid, colominic acid, and sialyllactose are all competitive inhibitors. The Vmax value in fibroblasts of a patient with mucolipidosis II was about 40 times lower than in normal control fibroblasts.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D005347:Fibroblasts / Q000201:enzymology*; D006801:Humans; D006923:Hymecromone / Q000031:analogs & derivatives / Q000378:metabolism*; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012709:Serum Albumin / Q000494:pharmacology; D013696:Temperature; D014468:Umbelliferones / Q000378:metabolism*
chemical_list: D012709:Serum Albumin; D014468:Umbelliferones; D006923:Hymecromone; C021224:2'-(4-methylumbelliferyl)-alpha-D-N-acetylneuraminic acid; D009439:Neuraminidase