Peptides mimicking the N-terminal Cu(II)-binding site of bovine serum albumin: synthesis, characterization and coordination with Cu(II) ions

N-terminal region of bovine serum albumin (Asp-Thr-His-Lys) is known to pro vide a specific binding site for Cu(II) ions, with the histidine residue th ought to be mainly responsible for the specificity. Thiomolybdates have bee n found to increase the binding affinity of Cu(II) to some serum albumins. As part of a series of studies to study the interactions between Cu(II), th iomolybdates and bovine serum albumin, we have performed the syntheses and characterization of small model peptides such as His-Lys, Thr(Ac)-His-Lys a nd Thr-His-Lys. Proton NMR spectra have been monitored in H2O solution as a function of pH and added Cu(II) concentration. Reliable K-a values for His -Lys and Thr(Ac)-His-Lys have been established. Probable binding sites of C u(II) and the relative strengths of binding to these peptides are also disc ussed. (C) 2001 Elsevier Science B.V. All rights reserved.