31P NMR correlation maps of 18O/16O chemical shift isotopic effects for phosphometabolite labeling studies

Intramolecular correlations among the O-18-labels of metabolic oligophosphates, mapped by J-decoupled P-31 NMR 2D chemical shift correlation spectroscopy, impart stringent constraints to the O-18-isotope distributions over the whole oligophosphate moiety. The multiple deduced correlations of isotopic labels enable determination of site-specific fractional isotope enrichments and unravel the isotopologue statistics. This approach ensures accurate determination of O-18-labeling rates of phosphometabolites, critical in biochemical energy conversion and metabolic flux transmission. The biological usefulness of the J-decoupled P-31 NMR 2D chemical shift correlation maps was validated on adenosine tri-phosphate fractionally O-18 labeled in perfused mammalian hearts.