Figure 9.

Sugars stimulate binding of SUS1 to plant microsomes. Equal amounts (0.75 pmol μL⁻¹) of full-length MBP-SUS1 were analyzed without added microsomes or mixed with equal amounts of carbonate-stripped apical leaf microsomes at pH 6.5 and residual (4 mm) Suc (duplicate reactions shown), or after addition of 150 mm Suc (duplicate reactions shown), Glc, or maltose. The controls and microsomes were pelleted, washed, and then probed on immunoblots (IB) with an antibody against MBP. Densitometry of these blots is displayed in the graph at the bottom.