Figure 10. Formation of the ferrohaem-HmuY complex during incubation of HmuY with deoxyhaemoglobin-agarose.

Haemoglobin-agarose was deoxygenated with sodium dithionite and maintained anaerobically during the reaction with HmuY. Concentration of haemoglobin was 16 µM (with respect to haemoglobin subunit) as was HmuY. See text for details. The absorbance below 375 nm is due to the presence of dithionite. A small amount of deoxyhaemoglobin (∼0.1% of the total) was released from the control deoxyhaemoglobin-agarose after 40 min incubation in the absence of HmuY.