title: Purification and partial characterization of lysosomal neuraminidase from human placenta.
abstract: Lysosomal neuraminidase and beta-galactosidase are present in a complex together with a 32-kDa protective protein. This complex has been purified and the different components have been dissociated using potassium isothiocyanate (KSCN) treatment. beta-Galactosidase remains catalytically active, but neuraminidase loses its activity upon dissociation. The inactive dissociated neuraminidase was purified by removing the remaining non-dissociated beta-galactosidase/protective protein complex using beta-galactosidase-specific affinity chromatography. The dissociated neuraminidase material shows two major polypeptides on SDS-PAGE with an apparent molecular mass of 76 kDa and 66 kDa. Subsequently the 32-kDa protective protein was dissociated from the beta-galactosidase/protective protein complex, and purified. Antibodies raised against the dissociated inactive neuraminidase preparation specifically immunoprecipitate the active neuraminidase present in the complex with beta-galactosidase and protective protein. By immunoblotting evidence is provided that the 76-kDa protein is a subunit of neuraminidase which, in association with the 32-kDa protective protein, is essential for neuraminidase activity.
mesh_terms: D000918:Antibody Specificity; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006801:Humans; D007120:Immunochemistry; D008247:Lysosomes / Q000201:enzymology*; D009439:Neuraminidase / Q000276:immunology / Q000302:isolation & purification*; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D011257:Pregnancy Proteins; D001616:beta-Galactosidase
chemical_list: D011257:Pregnancy Proteins; D009439:Neuraminidase; D001616:beta-Galactosidase