Synthesis and structural characterization of conjugates of adenosine and tetra-aspartate, novel analogs of ATP

Solid phase synthesis of conjugates of adenosine and tetra-aspartate, potential ligands of P2 (adenosine triphosphate) receptors, is described. Different spatial arrangement of the peptide chain relative to the adenosine moiety in these highly charged compounds is shown by 1H and 13C NMR spectroscopy. pKa values for the three internal aspartates and adenine base were determined.