抄録
Nucleotides, 5'-AMP, 5'-GMP, 5'-UMP, 5'-CMP and 5'-TMP, in D2O solution have been investigated by proton magnetic resonance spectroscopy. The concentration and the pD dependences of the proton chemical shifts of the nucleotides have been examined in detail. These results indicate that intermolecular association of vertical stacking of the base rings and intramolecular association between base protons and ionized phosphate group occur in solution. The effects of the temperature and lithium ion on 5'-AMP and 5'-UMP have been also investigated. The increase of temperature causes to reduce the intramolecular association for 5'-UMP and the both intra- and intermolecular association for 5'-AMP. Lithium ion reduces the intramolecular association for both 5'-AMP and 5'-UMP, and at the same time promotes the intermolecular one for the former. This can be interpreted by the ion-pair formation of lithium ion with the ionized phosphate group.
