Interaction of Cu(II)with His-Val-Gly-Asp and of Zn(II) with His-Val-His, Two Peptides at the Active Site of Cu,Zn-Superoxide Dismutase

His-Val-His and His-Val-Gly-Asp are two naturally occurring peptide sequences, present at the active site of Cu,Zn-superoxide dismutase (Cu,Zn-SOD). We have already studied the interaction of His-Val-His=A (copper binding site) with Cu(II) and of His-Val-Gly-Asp=B (zinc binding site) with Zn(II). As a continuation of this work and for comparison purposes we have also studied the interaction of Zn(II) with His-Val-His and Cu(II) with His-Val-Gly-Asp using both potentiometric and spectroscopic methods (visible, EPR, NMR). The stoichiometry, stability constants and solution structure of the complexes formed have been determined. Histamine type of coordination is observed for/ZnAH/2+, /ZnA/+, /ZnA2H/+ and/ZnA2/ in acidic pH while deprotonation of coordinated water molecules is observed at higher pH. /CUB/ species is characterized by the formation of a macrochelate and histamine type coordination. Its stability results in the suppression of amide deprotonation which occurs at high pH resulting in the formation of the highly distorted from square planar geometry 4N complex/CuBH-3/3

Copper(II) and zinc(II) complexes of the peptides Ac-HisValHis-NH 2 and Ac-HisValGlyAsp-NH2 related to the active site of the enzyme CuZnSOD

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Interaction of Cu2+ with His-Val-His and of Zn2+ with His-Val-Gly-Asp, two peptides surrounding metal ions in Cu,Zn-superoxide dismutase enzyme

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