Interaction of copper(II) and nickel(II) with L-histidine and glycylglycyl-L-histidine as an albumin model

Article abstract of DOI:10.1021/ic50206a012

The ternary system composed of Cu(II) (M), L-histidine (A), and glycylglycyl-L-histidine (B) designed to mimic the copper-transport site of serum albumin has been investigated by potentiometric titrations and spectroscopic measurements A solution equilibrium study (25°C; I = 0.1 (KNO₃)) indicated that the binary species CuH_-2B and CuA₂ are the main species while the ternary species CuAB is the minor one at physiological pH, and CuH_-2B is predominant in the higher pH region. This result coincides well with the absorption, CD, and ESR spectral behaviors of the ternary systems. The quite similar absorption and CD spectral behaviors were observed for the corresponding systems with Ni(II) in place of Cu(II). In order to shed light on details of the interaction of Cu(II) with B and A, we similarly investigated the ternary systems containing histamine or glycine in place of A. The biological copper transport mechanism in blood was discussed on the basis of both the above results and the information obtained by studies on exchange reactions of Cu(II) and Ni(II) complexes of B with A, histamine and glycine.