A spectrophotometric study of the binding of Cu(II) ions to ATP.
The interaction of copper(II) with adenosine triphosphate (ATP) has been studied as a function of pH in the range pH 3-12. Our approach is the study of the effect of binding both on the ATP ultraviolet absorption spectrum and on the optical d-d transition of copper ions. The results show that Cu(II)-ATP complexes exist in a variety of forms in equilibrium, the percentage of each species varying according to the state of ionization of the intrinsic adenine, phosphate and ribose groups. These results also show a close correlation between the rate of dephosphorylation of ATP in the presence of Cu(II) ions and Cu(II) bonding to the adenine of ATP, thus supporting the hypothesis that the metal-ion/nucleic-base interactions are crucial for the observation of a metal-ion promoted dephosphorylation of ATP (D.H. Buisson and H. Sigel, Biochim. Biophys. Acta 343 (1974) 45).
Onori
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Dipartimento di Fisica dell'Università, Perugia, Italy.
D000255:Adenosine Triphosphate; D055598:Chemical Phenomena; D002621:Chemistry; D003300:Copper; D006863:Hydrogen-Ion Concentration; D013053:Spectrophotometry
D003300:Copper; D000255:Adenosine Triphosphate