Abstract: The present invention concerns mouse brain sialidase gene activity. The invention further relates to nucleic acids encoding sialidase protein, vectors containing and capable of expressing such nucleic acid, and recombinant host cells transformed with such nucleic acid. The invention also provides an amino acid sequence encoding an enzymatically active sialidase that is active in eukaryotic cells. The invention also provides host cells transfected or transformed with recombinant vectors expressing the sialidase gene from mouse brain in the host cells.