title: Formation equilibria of nickel complexes with glycyl-histidyl-lysine and two synthetic analogues.
abstract: Complex-formation equilibria between the Ni(II) ion and the natural tripeptide glycyl-L-histidyl-L-lysine have been investigated. Two synthetic analogues, where the histidine residue has been substituted with L-4,5,6,7-tetrahydro-1H-imidazo[4,5-c]pyridine-6-carboxylic acid (L-Spinacine) and L-1,2,3,4-tetrahydro-isoquinolin-3-carboxylic acid (Tic), respectively, have been considered, as well. Different experimental techniques have been employed: potentiometry, calorimetry, visible spectrophotometry and CD spectroscopy. Structural hypotheses on the main complex species are suggested. Evidences on the formation of tetrameric species with the first ligand are shown. No involvement of the side-chain amino group of lysine residue in metal ion coordination was found.
authors.affiliation: Department of Chemistry, University of Ferrara, via L. Borsari 46, Ferrara I-44100, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Conato
authors.forename: Henryk
authors.initials: H
authors.lastname: Kozłowski
authors.forename: Jolanta
authors.initials: J
authors.lastname: Swiatek-Kozłowska
authors.forename: Piotr
authors.initials: P
authors.lastname: Młynarz
authors.forename: Maurizio
authors.initials: M
authors.lastname: Remelli
authors.forename: Sergio
authors.initials: S
authors.lastname: Silvestri
mesh_terms: D002151:Calorimetry; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008024:Ligands; D009532:Nickel / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry*; D011199:Potentiometry; D013056:Spectrophotometry, Ultraviolet; D013816:Thermodynamics
chemical_list: D008024:Ligands; D009842:Oligopeptides; C020905:glycyl-histidyl-lysine; D009532:Nickel