The Complex of β-Galactosidase, Neuraminidase and “Protective Protein” in Lysosomes: Molecular Characterization of the “Protective Protein”

Human lysosomal β-D-galactosidase and N-acetyl-α-neuraminidase (sialidase) are hydrolytic enzymes responsible for the degradation of a variety of natural and synthetic substrates (for review see [1,2]). They are associated in their functional state with a third glycoprotein, referred to as “protective protein” [3,4]. These three glycoproteins copurify as a complex, the molecular basis of which is so far poorly understood.