Cell surface human α-L-fucosidase

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 M r 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.