title: Phosphorus J coupling constants of ATP in human myocardium and calf muscle.
abstract: Proton-decoupled 31P NMR spectroscopy of the heart and calf muscle of healthy volunteers was performed with a 1.5 T whole-body imager. By use of two-dimensional chemical-shift imaging in combination with slice-selective excitation, well-resolved localized spectra (elements of 38 ml) were obtained within 20 to 35 min from which the homonuclear J coupling constants of ATP could be determined. In myocardium, J gamma beta = 16.03 +/- 0.17 Hz and J alpha beta = 15.82 +/- 0.23 Hz were obtained, while the values in calf muscle were J gamma beta = 17.16 +/- 0.12 Hz and J alpha beta = 16.04 +/- 0.09 Hz. The difference in J gamma beta was significant. According to the literature, a possible reason for greater ATP J coupling constants is a smaller fraction of ATP complexed to magnesium. However, the chemical-shift difference between alpha- and beta-ATP, which is also a measure for the fraction of ATP complexed to magnesium, showed only a small difference in ATP complexation: 88% in myocardium and 90% in calf muscle. This small difference cannot account for the observed difference in J gamma beta.
authors.affiliation: Hypertension and Diabetes Research Unit, Max Grundig Clinic, Bühl, Germany.
authors.forename: W I
authors.initials: WI
authors.lastname: Jung
authors.forename: S
authors.initials: S
authors.lastname: Widmaier
authors.forename: U
authors.initials: U
authors.lastname: Seeger
authors.forename: M
authors.initials: M
authors.lastname: Bunse
authors.forename: A
authors.initials: A
authors.lastname: Staubert
authors.forename: L
authors.initials: L
authors.lastname: Sieverding
authors.forename: K
authors.initials: K
authors.lastname: Straubinger
authors.forename: F
authors.initials: F
authors.lastname: van Erckelens
authors.forename: F
authors.initials: F
authors.lastname: Schick
authors.forename: G
authors.initials: G
authors.lastname: Dietze
authors.forename: O
authors.initials: O
authors.lastname: Lutz
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis*; D000293:Adolescent; D000328:Adult; D002614:Chelating Agents / Q000032:analysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007089:Image Enhancement; D008274:Magnesium / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D018482:Muscle, Skeletal / Q000737:chemistry*; D009206:Myocardium / Q000737:chemistry*; D010725:Phosphocreatine / Q000032:analysis; D010758:Phosphorus / Q000032:analysis*; D012815:Signal Processing, Computer-Assisted
chemical_list: D002614:Chelating Agents; D010725:Phosphocreatine; D010758:Phosphorus; D000255:Adenosine Triphosphate; D008274:Magnesium