Stopped-Flow Spectroscopic Studies on the Ligand-Exchange Reaction of Cu–(Glycine-Peptide) Complexes, Cu(H−iL), with Cysteine. Cu(II) Transport and Characterization of the Intermediate Ternary Complexes Cu(H−1L)(Cys−); L = Glycylglycine (i= 1), Triglycine (i= 2), Tetraglycine (i= 2 or 3), and Pentaglycine (i= 2 or 3)
| Autor: | Manabu Hiraoka, Toshikazu Abe, Akira Hanaki, Akira Odani, Yasuhiro Funahashi |
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| Rok vydání: | 2003 |
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| Zdroj: | Bulletin of the Chemical Society of Japan. 76:1747-1755 |
| ISSN: | 1348-0634 0009-2673 |
| Popis: | Cu(II) complexes of glycine-peptides, abbreviated as Cu(H−iL): L = glycylglycine, triglycine, tetraglycine, and pentaglycine (i = 1–3), react with cysteine to form ternary complexes, Cu(H−1L)(Cys−), as first intermediates. The spectral parameters of the ternary complexes, which were similar irrespective of the peptides, were as follows: λmax = 332 ± 1 nm (e = 4250 ± 50 M−1 cm−1), g|| = 2.170 ± 0.005, g⊥ = 2.00 ± 0.05, and A|| = (2.05 ± 0.01) × 10−4 cm−1, indicating that the ternary complexes have identical coordination structures: the Cu(II) coordinates with the peptides via the nitrogens from the terminal amino and the neighboring deprotonated-amide group, and with cysteine via the amino nitrogen and the thiolate sulfur. Based on the absorbance-time curves, the concentrations of each Cu(II) and Cu(I) species during the reaction were calculated. The species distribution curve clearly visualized the pathway of the Cu(II) transport from Cu(H−iL) to Cu(Cys−)2 via Cu(H−1L)(Cys−). The rate of Cu(H−1L)(Cys−) fo... |
| Databáze: | OpenAIRE |
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