Cell surface human α-L-fucosidase

Abstract

The acid α-L-fucosidase is usually found as a soluble component of lysosomes where fucoglycoconjugates are degraded. In the present investigation, we have demonstrated the existence of a cell surface protein with enzymatic α-L-fucosidase activity that crossreacts specifically with a rabbit anti-(α-L-fucosidase) Ig. By different approaches, this α-L-fucosidase, which represents 10-20% of the total cellular fucosidase activity, was detected in all the tested human cells (hemopoietic, epithelial, mesenchymal). Two bands of ≈43-49 kDa were observed, although theoretical data support the possibility of having the same genetic origin that the known 50 to 55-kDa Mr α-L-fucosidase. We speculate about an alternative traffic pathway for the plasma membrane α-L-fucosidase to work on the rapid turnover of glycoproteins.