抄録
Intracellular Mg2+ is known to affect many intracellular enzymes and other important cellular processes. In 31P-NMR spectrum, the observed chemical shifts of the ATP peaks indicate the ratio of metal-free to total ATP. Thereby, the intracellular Mg2+ concentration ([Mg2+]i) can be estimated from the chemical shifts of ATP peaks assuming the dissociation constant of MgATP (KD"MgATP"). pH is known to affect the KD"MgATP". McGuigan's group have shown that KD"MgATP" at 25 and 37°C are described as quadratic functions of pH (Zhang et al. Anal Biochem 251, 246-250, 1997). In this presentation, we estimate [Mg2+]i from the chemical shifts of intracellular ATP, using the formula modified for our experimental conditions. We will communicate the re-evaluated resting [Mg2+]i in smooth and cardiac muscles, and also show various modulations of [Mg2+]i caused by changing ionic substitutions and applying important hormones and drugs. [Jpn J Physiol 54 Suppl:S36 (2004)]
