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Interaction of V IV O, V V O 2 and Cu II with a Peptide Analogue SalGly‐ L ‐Ala
Author(s) -
Jakusch Tamás,
Dörnyei Ágnes,
Correia Isabel,
Rodrigues Lígia M.,
Tóth Gábor K.,
Kiss Tamás,
Pessoa João Costa,
Marcão Susana
Publication year - 2003
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200200511
Subject(s) - chemistry , deprotonation , ligand (biochemistry) , amide , tripeptide , dipeptide , chelation , stereochemistry , metal , electron paramagnetic resonance , crystallography , aqueous solution , medicinal chemistry , ion , peptide , inorganic chemistry , nuclear magnetic resonance , organic chemistry , biochemistry , physics , receptor
The formation of complexes of a tripeptide analogue, salicylglycyl‐ L ‐alanine [HOC 6 H 4 C(O)NHCH 2 C(O)NHCH(CH 3 )COOH, H 2 SalGly‐ L ‐Ala], was studied with Cu II , V IV O and V V O 2 in aqueous solution using pH‐potentiometric and spectroscopic (UV/Vis, CD, EPR and 51 V NMR) techniques. The results demonstrated the ambidentate character of the ligand. The metal ion‐induced deprotonation and subsequent coordination of the two neighbouring amide groups was shown to occur in a cooperative way in the pH range 5−6. At pH ≈ 6.5 a complex with an (O − , 2 × CON − , COO − ) binding set becomes predominant for both Cu II and V IV O. The affinity of the phenolate‐O − for V IV O is high and the ligand is bound to this metal ion even at pH values greater than 10. Conversely, the affinity for V V O 2 is significantly lower and no interaction between this metal oxo‐ion and the ligand could be detected in the pH range 2−12. In contrast, with the dipeptide analogue H 2 SalGly, chelation involving the deprotonated amide‐N − could be unambiguously detected. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)