title: Error in the calibration of the MgATP chemical-shift limit: effects on the determination of free magnesium by 31P NMR spectroscopy.
abstract: The measurement of free intracellular magnesium (Mg2+) using the 31P chemical shifts of ATP requires the use of appropriate calibration solutions to determine the chemical-shift limits delta ATP alpha beta and delta MgATP alpha beta. Solutions containing excess Mg2+ contain significant amounts of Mg2ATP and yield positive errors in the value of delta MgATP alpha beta. For physiological applications this may overestimate free intracellular Mg2+ by as much as 300%. This error may be minimized if appropriate mole ratios of Mg2+/ATP are used to calibrate delta MgATP alpha beta.
authors.affiliation: Department of Radiology, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey 17033.
authors.forename: T J
authors.initials: TJ
authors.lastname: Mosher
authors.forename: G D
authors.initials: GD
authors.lastname: Williams
authors.forename: C
authors.initials: C
authors.lastname: Doumen
authors.forename: K F
authors.initials: KF
authors.lastname: LaNoue
authors.forename: M B
authors.initials: MB
authors.lastname: Smith
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis* / Q000737:chemistry; D002138:Calibration; D006859:Hydrogen / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000032:analysis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010758:Phosphorus; D013054:Spectrophotometry, Atomic
chemical_list: D010758:Phosphorus; D006859:Hydrogen; D000255:Adenosine Triphosphate; D008274:Magnesium