Intrinsic fluorescence emission of intact oxy hemoglobins

Fluorescence has not been previously detected in intact hemoproteins. We have been able to measure significant fluorescence emission in purified oxy HbA using front-face fluorometry. The excitation maximum (293 nm), the emission maximum (325 nm) and the fluorescence spectra of Hb Rothschild (β 37 Trp → Arg) allows us to conclude that β 37 Trp is primarily responsible for the fluorescence signal of HbA. We propose that this intrinsic fluorescence of hemoglobin may be used as a probe to study conformational changes in hemoglobin and possibly other heme-containing proteins.