Fluorometric detection of adenosine triphosphate with 3-hydroxy-4 '-(dimethylamino)flavone in aqueous solutions

An effect of appearance of new band in the excitation spectra of 3-hydroxy-4'-(dimethylamino)flavone (FME probe) in presence of adenosine triphosphate (ATP) is described. Considerable shift of new band up to the red and increase of fluorescence intensity points to the formation of FME-ATP associate, in which FME molecule undergoes to a strong electrostatic stabilization by tetra-charged ATP anion. It is shown the FME anion formation is possible under influence of ATP in the studied conditions. The dynamics of the observed effect is studied in mitochondria. The registered phenomenon allows the quantitative evaluation of ATP concentration in the range of 10(-3)-10(-5) M. In contrast to ATP, other nucleoside phosphates do not give a new band in the excitation spectra of FME probe. This implies the possibility of the in vivo determination of the ATP concentration.