Interactions in solution of cobalt(II) and nickel(II) with nicotinamide adenine dinucleotide. A potenciometric and calorimetric study

HERRERO L. A.; CERRO-GARRIDO J.C.; APELLA M. C.; TERRÓN-HOMAR A.

JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY

Springer

Lugar: Berlin/Heilderberg; Año: 2002 vol. 7 p. 313 - 317

0949-8257

The equilibrium constants and the thermodynamic parameters enthalpy and entropy of the interaction between Ni(II) and Co(II) with NAD+ in aqueous solution were determined by calorimetry and potentiometry methods (ionic strength adjusted to 0.1 with sodium nitrate at 25 °C. The macrochelation of the systems was also studied. All the data, including the protonation enthalpy data of NAD+ (very similar to the protonation enthalpy of 5´-AMP) suggest a less restrictive model for the NAD+ conformation without intramolecular stacking between the bases, in agreement both with recent theoretical calculations and with the X-ray structure of trimethylene-bisadeninium or the free acid form of NAD+.