l-Histidine-containing Peptides as Models for the Interaction of Copper (II) and Nickel (II) Ions with Sperm Whale Apomyoglobin

• Published in: The Journal of biological chemistry Vol. 241; no. 5; pp. 1072 - 1080
• Main Authors: Bryce, G F, Roeske, R W, Gurd, R N
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 10.03.1966
• Subjects: Animals; Cetacea; Chemical Phenomena; Chemistry, Physical; Copper; Histidine; In Vitro Techniques; Ions; Myoglobin; Nickel; Peptides
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)96804-3

1. The association and ionization constants for nickel (II) and a selection of l -histidine-containing peptides have been computed together with the constants for copper (II) and acetylglycylglycyl- l -histidylglycine. 2. A close parallel between the titration behavior of copper (II) apomyoglobin complexes and model peptides has been obtained on the assumption that 1 of the 4 bound metal ions is situated at the NH 2 -terminal portion of the polypeptide chain. 3. Visible absorption spectra of nickel (II) and copper (II) apomyoglobin complexes containing 4 metal ions per mole have been measured and found to be consistent with the binding of 1 metal ion at the NH 2 -terminal locus and 3-metal ions in the interior of the peptide chain at histidine loci. 4. Optical rotatory dispersion and circular dichroism spectra in the visible region have been measured for both the protein and the peptide complexes. Strict similarities were not, in general, found and the various explanations for this failure are discussed.