Fig. 5.
Effect of manganese on the absorption spectra of heme bound to purified recombinant Irr. (A) Shows 8 μM Irr and 4 μM heme, in the presence of 100 μM dithionite as a reductant, and the absorption spectrum taken between 380 and 480 nm. The sample was then titrated with 2, 4, 6, 8, 10, 20 μM MnCl2, and the spectrum was taken after each addition. The maximum peak was observed with no metal, and the minimum absorption at 20 μM MnCl2. (B). The experiment was carried out as described in A, using either no metal (none), 20 μM ZnCl2 (Zn), or 20 μM FeSO4 (Fe).