Figure 3.

Effect of Mn²⁺–bicarbonate complexes on the re-reduction of P⁺ in the pigment–protein complexes B890 from Rh. iodosum at various concentrations of (a) bicarbonate and (b) MnCl₂.The experiments shown in (a) were done in the presence of 0.5 mM MnCl₂ without other additions (filled squares) and after the addition of 30 (open triangles), 40 (open diamond), 50 (filled circles) and 75 mM (open inverted triangles) of NaHCO₃.The experiments shown in (b) were done in the presence of 50 mM NaHCO₃ without other additions (filled squares) and after the addition of 0.01 (open triangles), 0.1 (open diamond), 0.3 (filled circles) and 0.5 mM (open inverted triangles) of MnCl₂.The results are an average of three experiments.