1,8-Anilinonaphthalene sulfonate binds to central cavity of human hemoglobin

Binding of 1,8-anilinonaphthalene sulfonate (1,8-ANS) to main (HbA(1)) and glycosylated (HbA(1C)) forms of human oxyhemoglobin in the presence/absence of inositolhexaphosphate (IHP) in 50 mM potassium phosphate buffer, pH 7.4, was studied by time-correlated single photon counter with subnanosecond time resolution. The redistribution of contributions of the most long-lived and the most short-lived fluorescent decay components in the presence of IHP provides an evidence of the probe binding within oxyhemoglobin central cavity, namely DPG-binding site. Finally, it was shown that the fluorescent probe is extremely sensitive for hemoglobin central cavity modification, provided by the carbohydrate moiety in case of 1,8-ANS interactions with HbA(1C).