Absence of reaction is hinted at by unchanged optical spectra and made
apparent by ECL assay of denaturing gels, which detects heme only in
the dye front of DT-treated CtrHbs (Fig. 4a, lanes 1–3). In this assay
Synechocystis GlbN-A shows a strong signal at the protein's molecular
weight (Fig. 4a, lane 4), as expected. The NMR spectra of the treated
CtrHbs are not presented as they are identical to those of the nonreduced
starting material.
Failure to react can be due to various factors, including heme dissociation,
incorrect histidine–vinyl geometry or unfavorable electron