Purification and characterization of cytosolic sialidase from rat liver.

摘要: Sialidase has been purified from rat liver cytosol 83,000-fold by sequential chromatography on DEAE-cellulose, CM-cellulose, Blue-Sepharose, Sephadex G-200, and heparin-Sepharose. When subjected to sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis, the cytosolic sialidase moved as a single protein band with Mr = 43,000, value similar that obtained sucrose density gradient centrifugation. The enzyme was active toward all of sialooligosaccharides, sialoglycoproteins, gangliosides tested except for submaxillary mucins GM1 GM2 gangliosides. Those substrates possessing alpha 2----3 sialyl linkage were hydrolyzed much faster than those 2----6 or 2----8 linkage. optimum pH 6.5 sialyllactose 6.0 orosomucoid mixed brain activity lost progressively progress purification but restored addition proteins such bovine serum albumin. In contrast, neither reduction nor restoration albumin observed orosomucoid. substrate, bile acids required this requirement became almost absolute after had extensively. Intracellular distribution study showed about 15% neutral in microsomes. could be released 0.5 M NaCl; indistinguishable properties.