Fluorescence emission from ligated complexes of Tyr⁵⁷Trp FBPase.

F – relative mean fluorescence emission at maximum from the Tyr57Trp mutant in the presence of F6P (5 mM) and KPi (5 mM). λmax – a mean λmax from three independent experiments. Mean values from three independent experiments are presented in the table. An increasing concentration of Mg2+ and Zn2+ (down to the first column) induces significant (p<0.005) changes in the fluorescence (full circle) and a slight red-shift (empty circle – p<0.05) as compared to the fluorescence measured in the absence of the cations. Asterisk indicates a significant difference (** - p<0.005, * - p<0.05) in fluorescence upon addition of AMP or Ca2+ to the enzyme saturated with various concentrations of Mg2+ and Zn2+. nd - not detected.