Please use this identifier to cite or link to this item:
https://hdl.handle.net/10316/3898
Title: | Comparison of Fluorescence, 31P NMR, and 7Li NMR Spectroscopic Methods for Investigating Li+/Mg2+ Competition for Biomolecules | Authors: | Amari, Louis Layden, Brian Rong, Qinfen Geraldes, Carlos F. G. C. Freitas, Duarte Mota de |
Keywords: | lithium; biomolecules; ATP; NMR; fluorescence | Issue Date: | 1999 | Citation: | Analytical Biochemistry. 272:1 (1999) 1-7 | Abstract: | The biochemical action of lithium in the treatment of manic-depressive illness is still unknown. One hypothesis is that Li+ competes for Mg2+-binding sites in biomolecules. We report here our studies on metal ion competition by three distinct methods: fluorescence, 31P NMR, and 7Li NMR spectroscopy, using ATP as a model ligand. By fluorescence spectroscopy, we used the dye, furaptra, by measuring the increases in Mg2+ levels in an ATP solution as Li+ levels were increased in the solution. This increase in Mg2+ levels was indicated by increases in the fluorescence intensity ratio (335/370) of furaptra. By 31P NMR spectroscopy, this competition was demonstrated by changes in the 31P NMR spectrum of ATP. The Li+/Mg2+ competition was indicated by predictable changes in the separation between the [alpha] and [beta] resonances of the phosphates of ATP. For 7Li NMR spectroscopy, spin-lattice relaxation measurements were used, which provided free Li+ concentrations that could be used for determining the free Mg2+ values in ATP solutions. The values of the free Mg2+ concentrations obtained by all three methods were in good agreement. The fluorescence and 7Li NMR methods, however, proved to be more sensitive to low concentrations of Li+ than the 31P NMR method. | URI: | https://hdl.handle.net/10316/3898 | DOI: | 10.1006/abio.1999.4169 | Rights: | openAccess |
Appears in Collections: | FCTUC Ciências da Vida - Artigos em Revistas Internacionais |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
file79850932118d4df1bd29ed2f37e5279c.pdf | 154.83 kB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.