Intramolecular interligand interaction in zinc(II) and cadmium(II) mixed ligand complexes of ATP and aminoacids or dipeptides or phenolic compounds

摘要

The stability constants of (MATPL) complexes in aqueous medium have been determined poteatiometrically, at 25°C and at an ionic strength of 0.2 M (NaClO_4), by using the SCOGS computer program, where M = Zn(II) or Cd(II), ATP = adenosine 5'-triphosphate, L = alpha-alanine (Ala), phenylalanine (Phe), L-tyrosine (Tyr), L-tryptophan (Trp), glycyl glycine (gg), glycyl L-alanine (ga), catechol (cat), orthoaminophenol (oap) and 2,3-dihydroxy naphthalene (dhn). The stability of these ternary complexes is discussed in terms of Alog k values. Probable reasons for the stabilization or destabilization of the ternary complexes are suggested, with reference to the tetrahedral geometry of the complexes, a point of relevance in the environment around Zn(II) in the metalloeozyme.