Abstract
Quantum yields for pyridoxal, pyridoxamine, and pyridoxamine-5-phosphate at 25°C in neutral aqueous solution were 0.048, 0.11, and 0.14, respectively. The fluorescence efficiencies were highly temperature-dependent, and the compounds were extremely sensitive to light. There were marked discrepancies between the values obtained in this study for quantum yield and fluorescence polarization of pyridoxamine-5-phosphate and the values recently reported by others.