Figure 2

The uptake of d -phenylglycine- l -dopa in BBMV with or without the presence of l -Phe, l -dopa, l -Gly- l -Pro, l -Gly- l -Phe and cephradine (**: p < 0.01; ***: p < 0.001.). The BBMV was prepared according to material and methods. The BBMV preparation (20 ml containing approximately 20 mg protein/ml) was added into 200 ml of a reaction buffer (composed of 300 mM mannitol, 25 mM HEPES/Tris buffer pH 7.4, (pH was adjusted by adding MES) and the test solution (to 1 - 2 mM of final conc.) was added. After incubation at room temperature for acquired time, an ice-cold stop solution (1.5 ml) containing NaCl (150 mM) and HEPES/Tris (16 mM, pH 7.4) was added and the solution was filtered through a filter paper (Whatman WCN, 0.45 μm pore size, 2.5 cm diameter) under a vacuum. The filter paper was washed twice with 3 ml of the same stop solution. The test compound remained on the filter paper were extracted with 0.5 ml of 0.01 M aqueous HCl solution by virtue of a vortex motion. The solution (100 μl) was injected onto the HPLC column. Test compound bound on the filter paper was determined for correction in different runs using preparations without BBMV added.