N-Glycosylation of PZ. (A) Stably transformed cells were treated with 5μg/mL tunicamycin (Tun) for 24 hours in the presence or the absence of vitamin K. (B) Treatment of PZ with an endoglycosidase H (EndoH). Protein (10 μg) of cell lysate was treated with 2 mU EndoH for 24 hours and subjected to SDS-PAGE/Western blotting. N-glycosylation of PZs was completely suppressed by Tun treatment, and the carbohydrate moiety of PZs was removed by EndoH digestion.