Stabilization of the T-state of human hemoglobin by proflavine, an antiseptic drug

The effect of proflavine (3,6-diaminoacridine), an antiseptic drug, on the spectroscopic and oxygen binding properties of ferrous human adult hemoglob in (Hb) has been investigated. Upon binding of proflavine to the nitric oxi de derivative of ferrous human adult hemoglobin (HbNO), the X-band EPR spec trum displays the characteristics which have been attributed to the T-state of the ligated tetramer. in parallel, oxygen affinity for the deoxygenated derivative of ferrous human adult Hb decreases in the presence of proflavi ne. The effect of proflavine on the spectroscopic and ligand binding proper ties of ferrous human adult Kb is reminiscent that of 2,3-D-glycerate bisph osphate, the physiological modulator of Hb action.