The chemical shifts of the 170 resonances associated with the bridging and nonbridging oxygens of pyrophosphate have been unambiguously assigned; this information allows the assignment of the resonances of all of the phosphoryl oxygens of ADP and ATP. The chemical shifts of the phosphoryl oxygens in pyrophosphate and several nucleotide analogues with predictable proton ionization behavior, i.e., AMPS, ATPyS, methylphosphonate, methylenediphosphonate, and the ²,y-methylene analogue of ATP, have been measured as a function of pH; in each case an upfield change in chemical shift is observed upon protonation, with the magnitude of the shift change being approximately 50 ppm. These observations and those previously described (Gerlt, J. A.; Demou, P. C; Mehdi, S. J. Am. Chem. Soc. 1982, 104, 2848) demonstrate that 170 NMR spectroscopy can be used to quantitate the site and degree of charge neutralization in phosphate ester anions and related species.
ASJC Scopus subject areas
- Colloid and Surface Chemistry