FIG. 2.

Ability of Pch-metal complexes to inhibit Pch-⁵⁵Fe uptake. Pvd- and Pch-deficient PAD07 cells at an OD₆₀₀ of 1 were incubated for 45 min in the presence of 100 nM Pch-⁵⁵Fe at 37°C. The mixtures were then filtered and radioactivity counted. The amount of ⁵⁵Fe transported in this experiment was used as a reference (defined as 100% uptake). This experiment was repeated in the absence of cells (bars labeled “Buffer”). The experiment was also repeated in the presence of cells and an excess of metal-free Pch and in the presence of cells and of each Pch-metal complex (black and white bars correspond to 1 and 10 μM metal, respectively). Pch-metal complexes were prepared by preincubating each metal in the presence of a 20-fold excess of Pch overnight. As a control, for each metal tested, the experiment was repeated in the absence of cells (data not shown). All the data are means and standard deviations from three independent experiments. The black line indicates the 100% of Pch-⁵⁵Fe uptake, and the gray line shows that most of the Pch-metal complexes inhibited 28% of the Pch-⁵⁵Fe uptake.