Reactivities and Site-Selectivities of Hydrolyses of ATP and UTP Promoted by Metal Complexes of Adenine-Linked Di-2-pyridylamine Derivatives

Article abstract of DOI:10.1246/bcsj.69.765

The reactivities and the site-selectivities of the hydrolyses of ATP and UTP by the catalysts of the metal complexes of adenine-linked di-2-pyridylamine ligands, (Py)₂N-(CH₂)_n-Ade (L: n = 3, 4, 5, and 6), were examined. It was found that these adenine-dipyridylamine coordinated Cu²⁺ complexes (with 2:1 ratios of [Cu^II(L)]²⁺ : ATP or [Cu^II(L)]²⁺ : UTP) were more reactive for the hydrolyses of ATP and UTP than the complexes of ligands containing other metal ions (Mg²⁺, Ni²⁺, and Zn²⁺) at 40°C and pH 7.3 (HEPES buffer), as reflected in much higher product ratios of ADP/AMP and UDP/UMP than those of Cu²⁺ alone. The observed high reactivity and selectivity are interpreted in terms of the base-base stackings between an adenine moiety of ATP or an uracil moiety of UTP and an adenine of the ligands, and of the selective coordination of Cu²⁺ to oxide ions in phosphate residues in the ternary complexes of ligand-Cu²⁺-ATP. The Cu²⁺-complex of di-2-pyridylamine having no adenine moiety, which is the active center of [Cu^II(L)]²⁺, promoted the hydrolyses of ATP and UTP less efficiently than the aquacopper(II) ion. The number of spacer methylene groups of the ligands influenced the hydrolytic activity of the Cu²⁺-complexes of these adenine-dipyridylamine ligands. The complexes of [Cu^II(L-4)]²⁺ and [Cu^II(L-5)]²⁺ were the most reactive and site-selective for the hydrolyses of ATP and UTP, respectively.