Sialidase Activity in Nuclear Membranes of Rat Brain

Authors

  • Megumi Saito,

    Corresponding author
    1. Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, U.S.A.
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  • Christian L. Fronda,

    1. Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, U.S.A.
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  • Robert K. Yu

    1. Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, U.S.A.
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Address correspondence and reprint requests to Dr. M. Saito at Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Box 614, Richmond, VA 23298-0614, U.S.A.

Abstract

Abstract: A highly purified nuclear membrane preparation was obtained from adult rat brain and examined for sialidase activity using GM3, GD1a, GD1b, or N-acetylneuramin lactitol as the substrate. The nuclear membranes contained an appreciable level of sialidase activity; the specific activities toward GM3 and N-acetylneuramin lactitol were 20.5 and 23.8% of the activities in the total brain homogenate, respectively. The sialidase activity in nuclear membranes showed substrate specificity distinct from other membrane-bound sialidases localized in lysosomal membranes, synaptosomal plasma membranes, or myelin membranes. These results strongly suggest the existence of a sialidase activity associated with the nuclear membranes from rat brain.

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