Figure 7.

Uptake of GDP-Fuc into Golgi vesicles in the presence of UDP-Glc, GMP, and DIDS. A, Golgi vesicles (100 μg of protein) were incubated with 1 μm GDP-[³H]Fuc (specific activity, 1 μCi/nmol) for 5 min at 25°C in the presence of increasing concentrations of cold GDP-Fuc or UDP-Glc. The reaction was terminated and the uptake determined as described in the legend to Figure 4. B, Uptake of 1 μm UDP-[³H]Glc (specific activity, 1 μCi/nmol) into Golgi vesicles in the presence of cold GDP-Fuc or UDP-Glc was performed as described in A. C, Effect of 50 μm GMP and 20 μm DIDS on the uptake of GDP-Fuc was determined by adding them separately in the incubation medium.