The first attempt at producing CtrHbs with covalently attached
heme was based on results obtained with Synechococcus and
Synechocystis GlbNs. For these proteins to undergo the reaction, it suffices
to reduce the heme iron [39]. Ferric T111H and L75H CtrHb were
incubated with excess DT for variable periods of time, up to ~2 h,
oxidized with potassium ferricyanide, and then exposed to an excess
of KCN for NMR comparison with their respective untreated form.