Ecto-5′-nucleotidase activity measured in membrane protein preparations of Arabidopsis plants expressing Pro35S::E5′NT (#303), Pro35S::SPE5′NT:mCherry:E5′NTwoSP (#304) or Pro35S::mCherry (#305). E5′NT activity was measured after incubation with 100 µM of either ATP, ADP or AMP. In the membrane protein preparations from Pro35S::E5′NT (#303) lines phosphate release was specifically increased upon incubation with purines. Error bars represent the standard error of the mean from three technical repetitions. The coomassie stained SDS-PAGE shows the protein pattern of the membrane fractions for the individual transgenic lines. Equal volumes were loaded. The experiment was repeated two times with similar results. 