Cu(II) binding by angiotensin II fragments: Asp-Arg-Val-Tyr-Ile-His and Arg-Val-Tyr-Ile-His. Competition between amino group and imidazole nitrogens in anchoring of metal ions

Copper(II) complexes of Neobelliera Bullata Trypsin Modulating Oostatic Factor and its analogues

“…The first protonation constant for the DPTNLH and NPTNLH peptides, log b = 7.89 and 7.43, respectively, refers to protonation of the N-terminal amine group and these values compare well with literature values [26][27][28]. The next protonation constant observed for all ligands studied, log K = 7.18-6.38 corresponds to protonation of the imidazole nitrogen of the His residue [29,30].…”

“…The coordination of metal ion starts at pH around 3.5 and the CuL complex with the maximum concentration at pH about 6.2 is formed (Fig. 1) [26]. c Ref.…”

The role of terminal amino group and histidine at the fourth position in the metal ion binding of oligopeptides revisited: Copper(II) and nickel(II) complexes of glycyl-glycyl-glycyl-histamine and its N-Boc protected derivative

“…The metal binding features of oligopeptides, including the effect of the number and position of histidine residues within the peptide chain have been summarized in a couple of reviews within the last decade [1,9,10]. There have been a number of systematic studies attempting to explore the role of the terminal amino group and a histidine at the fourth or higher position in the peptide sequence, as primary coordination sites for copper(II) and nickel(II) [11][12][13][14][15][16]. However, the obtained results were sometimes contradictory and generated some debates.…”

Cd(II) Capture Ability of an Immobilized, Fluorescent Hexapeptide

“…Data could be well fitted by considering four consecutive deprotonation steps corresponding to dissociation of the two cysteine sidechain thiol and two tyrosine sidechain phenol groups. The determined pK a values (shown in Table 1) fall in the range characteristic to Cys 33,51 and Tyr residues 55,56 within a peptide chain.…”