Spectral evidence for heme transfer from hemoSeShp to apoSeHtsAHis. (A) The shift over time in the visible spectrum of a mixture containing 4 μM hemoSeShp and 6 μM SeHtsAHis. The spectra (solid curves) were taken at 0, 90, 165, 315, 540, 990 seconds after mixing. The dashed line is the sum of the spectra of 4 μM hemoSeShp and 6 μM SeHtsAHis. (B) The spectral change in the visible region after mixing 4 μM hemoSeShp and 6 μM SeHtsAHis with excess dithionite. The spectra were recorded immediately (solid curve) and 6 min after mixing (dotted grey curve). The spectrum of hemoSeShp is included as a reference for change (dashed curve). The spectra were normalized for comparison. Insert: the same spectra in the region from 510 to 590 nm. The arrows indicate the directions of the spectral changes with time.