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PROPERTIES OF ACID β‐ d ‐GALACTOSIDASE ISOLATED FROM I‐CELL DISEASE BRAIN AND SPLEEN
Author(s) -
Miller Arnold L.,
Levitt Pat,
Ingraham Holly,
Converse James,
Lewis Linda
Publication year - 1979
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1979.tb11088.x
Subject(s) - concanavalin a , neuraminidase , spleen , isoelectric focusing , enzyme , biochemistry , sialic acid , cell , isoelectric point , ganglioside , biology , galactoside , chemistry , microbiology and biotechnology , immunology , in vitro
— Acid 4‐methylumbelliferyl β‐ d ‐galactosidase activity from autopsied I‐cell disease brain and spleen tissues was 28% and 35% respectively of normal activity. Acid β‐ d ‐gatactosidase (β‐ d ‐galactoside galactohydrolase, EC 3.2.1.23) from two I‐cell disease brains demonstrated a 5‐fold increase over normal for the proportion of enzyme activity which did not adsorb to Concanavalin A‐Sepharose 4B, while acid β‐ d ‐galactosidase from two I‐cell disease spleens demonstrated a 21–35‐fold increase in the proportion of unadsorbed enzyme activity. Normal and I‐cell disease acid β‐ d ‐galactosidase present in crude brain and spleen supernatant fluids and in preparations partially purified on Concanavalin A‐Sepharose 4B had similar apparent K m values with respect to 4‐methylumbelliferyl β‐ d ‐galactopyranoside and G M1 ‐ganglioside. Isoelectric focusing profiles of normal and I‐cell disease acid β‐ d ‐galactosidase from crude brain and spleen‐supernatant fluids and partially purified preparations were similar. Neuraminidase treatment and subsequent isoelectric focusing of the partially purified normal and I‐cell disease enzyme preparations from brain and spleen revealed increases in the proportion of I‐cell β‐ d ‐galactosidases found at neutral pH values, suggesting that the electrophoretic variations observed for the I‐cell enzymes may not be attributed solely to changes in sialic acid composition.