Decomposition Kinetics of Ni(III)−Peptide Complexes with Histidine and Histamine as the Third Residue
作者:Teweldemedhin M. Tesfai、Brandon J. Green、Dale W. Margerum
DOI:10.1021/ic049338a
日期:2004.10.1
The transition from first- to second-order kinetics is attributed to the formation of an oxo-bridged Ni(III)-peptide dimer. The rates of decay of the Ni(III) complexes are general-base assisted with Bronsted beta values of 0.62 and 0.59 for Ni(III)Gly(2)HisGly and Ni(III)Gly(2)Ha, respectively. The coordination of Gly(2)HisGly and Gly(2)Ha to Ni(II) are examined by UV-vis and CD spectroscopy. The square
Oxidative Self-Decomposition of the Nickel(III) Complex of Glycylglycyl-<scp>l</scp>-histidylglycine
作者:Brandon J. Green、Teweldemedhin M. Tesfai、Yi Xie、Dale W. Margerum
DOI:10.1021/ic035034x
日期:2004.2.1
above p[H+] 7.0, two Ni(III)-peptide complexes coordinate via an oxo bridge in the axial positions to form a reactive dimer species. This dimer generates two Ni(II)-peptide radical intermediates that cross-link at the alpha carbons of the N-terminal glycyl residues. In 0.13 mM Ni(III)-peptide at p[H+] 10.3, this pathway accounts for 60% of the reaction. The cross-linked peptide is subject to oxidation