Activator-dependent hydrolysis of myelin cerebroside sulfate by arylsulfatase A.
A purified myelin preparation containing [35S]-labeled cerebroside sulfate (CS) was biosynthesized in developing rat brain and tested as a model of a physiological substrate for CS hydrolysis by arylsulfatase A. Particular attention was directed to the involvement of the CS sulfatase activator protein in facilitating the catabolic process. Although arylsulfatase A alone was incapable of desulfating CS in either purified CS suspensions or the physiological membrane, activator-induced hydrolysis of myelin CS exhibited concentration dependency, pH optimum, and relative insensitivity to salts in a manner similar to purified lipid suspensions. Exogenous protein demonstrated concentration-dependent inhibition. Slower rates of hydrolysis observed for the myelin membrane substrate are proposed to be a consequence of myelin membrane configuration and competition for activator by other lipoidal constituents.
University of California at Los Angeles School of Medicine, Mental Retardation Research Group, Lanterman Developmental Center, Pomona.
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AI
Louis
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Fluharty
D000818:Animals; D001921:Brain / Q000378:metabolism*; D002458:Cell Fractionation; D002553:Cerebroside-Sulfatase / Q000378:metabolism*; D002554:Cerebrosides / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D009186:Myelin Sheath / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D002554:Cerebrosides; D002553:Cerebroside-Sulfatase