Figure 3.

Effect of ampicillin-degradation products on the ion current across a single active reconstituted trimeric OmpF channel (left) and the corresponding all point ion current amplitude histogram (right). OmpF was added to the cis = ground side, the applied voltage was ±100 mV, and the buffer contained 1 m KCl, buffered with 20 mm MES, pH 6.0. Cis/trans ampicillin-degradation product addition was measured separately. Note that 20 mm ampicillin-degradation product corresponds to 20 mm ampicillin. A, ion current in the absence of substrate. B, addition of 20 mm ampicillin-degradation product (DG) on the cis side (cis side is connected to the electrical ground). C, addition of 20 mm ampicillin-degradation product on the trans side.