Potential pitfall in the determination of free [Mg2+] by 31P NMR when using the β/α-ATP peak height ratio method

✍ Scribed by Widmaier, S

• Publisher: Springer
• Year: 1999
• Tongue: English
• Weight: 121 KB
• Volume: 9
• Category: Article
• ISSN: 0968-5243
• DOI: 10.1016/s1352-8661(99)00034-4

✦ Synopsis

Recently, Clarke et al. (Clarke K, Kashiwaya Y, King MT, Gates D, Keon CA, Cross HR, Radda GK, Veech RL. The b/a peak height ratio of ATP. A measure of free [Mg 2 + free ] using 31 P NMR, J. Biol. Chem. 1996;271:21142-21150.) reported a new method to noninvasively determine the concentration of intracellular free magnesium ([Mg 2 + free ]) based on the measurement of the peak height ratio h b/a of the band a-ATP signals in 31 P NMR spectra. h b/a varies with [Mg 2 + free ], however, the study presented here shows that h b/a also strongly depends on the homogeneity of the static magnetic field. For this reason, we performed at a magnetic field strength of 1.5 T 31 P NMR measurements of solutions that mimic intracellular medium. The magnetic field homogeneity was varied by changing the currents in the shim coils, and the effect on h b/a is demonstrated with and without proton decoupling. In both cases, h b/a strongly depends on the magnetic field homogeneity and can therefore lead to a pitfall in the determination of [Mg 2 + free ].