The determination of the Mg2+.ATP dissociation constant by competition with Eu3+ ion using laser-induced Eu3+ ion luminescence spectroscopy.
A direct spectroscopic method for the determination of the submicromolar dissociation constant of Eu3+. ATP using laser-induced Eu3+ ion luminescence spectroscopy is described. The dissociation constant of Mg2+.ATP is then determined by the competition of Mg2+ with Eu3+ for the binding of ATP. The experiments were performed in 2H2O to mitigate the significant quenching of the Eu3+ luminescence that occurs in 1H2O. Values for the effective dissociation constants of the 1:1 ATP metal ion complexes of 1.2 +/- 0.3 X 10(-7) and 2.7 +/- 0.7 X 10(-4) M are obtained for Eu3+ and Mg2+, respectively, at p2H 5.8.
McNemar
C W
CW
Department of Chemistry, Pennsylvania State University, University Park 16802.
Horrocks
W D
WD
D000255:Adenosine Triphosphate / Q000378:metabolism*; D001667:Binding, Competitive; D005063:Europium / Q000378:metabolism*; D007700:Kinetics; D007834:Lasers; D008163:Luminescent Measurements; D013057:Spectrum Analysis
D005063:Europium; D000255:Adenosine Triphosphate