Fig. 2.

Illustration of proteoliposome uptake assay after reconstitution of total leaf membrane protein from transgenic lines and wild-type controls. Uptake of [¹⁴C]malate (from outside into the inside of liposome) was measured with 30 mM or without (w/o) pre-loading of unlabeled malate inside the proteoliposome. Transport was initiated by adding [¹⁴C]malate to a final concentration of 0.3 mM (A). Uptake of malate into liposomes reconstituted with total crude membrane protein isolated from three different transgenic OMT1 lines, overexpressing ZmOMT1 (OMT1-79, OMT1-80, and OMT1-87), preloaded with either 30 mM malate (closed squares) or without preloading (closed circles) respectively. Liposomes reconstituted with total crude membrane protein isolated from WT plants, preloaded with either 30 mM malate (open squares) or without preloading (open circles) respectively served as controls. Values represent the arithmetic means ± SEM, n = 3 (B).