nmr and infrared spectroscopic investigations of the Al(III), Ga(III), and Be(II) complexes of ATP

The interaction of Al(III) with ATP has been examined by 31P and 1H nmr and infrared spectroscopy. At pH 6.2, Al(III) forms a long-lived complex with ATP, in which chemical exchange between free and complexed ATP is slow on the nmr time scale. Infrared spectra of the Al(III)-ATP complex exhibit large perturbations in the band corresponding to the -PO32− antisymmetric stretching mode. At higher pH values, equilibria involving Al(III) and OH− become favored with the result that Al(III) no longer influences the spectroscopic properties of ATP. Similar spectroscopic results are obtained for the Ga(III) and Be(II) complexes of ATP.