Mannosidosis: separation and characterization of two acid alpha-mannosidase forms in mutant fibroblasts.
Two acidic forms of alpha-mannosidase activity, A and B, are separated and characterized in fibroblasts from controls and patients with mannosidosis. In normal cells, A and B differ in adsorption on DEAE-cellulose, electrophoretic mobility, stability at 70 degrees C and resistance to freezing at --20 degrees C. In 5 of 6 mutant cell lines, A and B both exhibit altered Km's for artificial substrates and decreased thermal stability. Zn2+ has no effect on A or B in mutant or normal cells. In contrast, Co2+ slightly inhibits B in normal cells but markedly enhances the activity of B in mutant cells. The mutation in mannosidosis clearly results in an alteration in the biochemical characteristics of both major acidic forms of alpha-mannosidase.
D002239:Carbohydrate Metabolism, Inborn Errors / Q000201:enzymology*; D002413:Cations, Divalent / Q000494:pharmacology; D005347:Fibroblasts / Q000201:enzymology; D005615:Freezing; D006027:Glycosides / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D007526:Isoelectric Point; D007700:Kinetics; D008361:Mannosidases / Q000032:analysis* / Q000172:deficiency / Q000378:metabolism; D008362:Mannosides / Q000378:metabolism*
D002413:Cations, Divalent; D006027:Glycosides; D008362:Mannosides; D008361:Mannosidases