The determination of the Mg2+·ATP dissociation constant by competition with Eu3+ ion using laser-induced Eu3+ ion luminescence spectroscopy

✍ Scribed by Charles W. McNemar; William DeW. Horrocks Jr.

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 419 KB
• Volume: 184
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(90)90007-v

✦ Synopsis

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 'Hz0 to mitigate the significant quenching of the Eu3+ luminescence that occurs in 'HzO. Values for the effective dissociation constants of the 1:l ATP.metal ion complexes of 1.2 k 0.3 X lo-' and 2.7 + 0.7 X low4 M are obtained for Eu3+ and Mg'+, respectively, at p2H 5.8.