Interaction of V^IVO, V^VO₂ and Cu^II with a Peptide Analogue SalGly‐L‐Ala

Abstract

The formation of complexes of a tripeptide analogue, salicylglycyl‐L‐alanine [HOC6H4C(O)NHCH2C(O)NHCH(CH3)COOH, H2SalGly‐L‐Ala], was studied with CuII, VIVO and VVO2 in aqueous solution using pH‐potentiometric and spectroscopic (UV/Vis, CD, EPR and 51V 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 CuII and VIVO. The affinity of the phenolate‐O− for VIVO is high and the ligand is bound to this metal ion even at pH values greater than 10. Conversely, the affinity for VVO2 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 H2SalGly, chelation involving the deprotonated amide‐N− could be unambiguously detected. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Interaction of [VIVO(acac)2] with Human Serum Transferrin and Albumin

“…In the visible range, because the protein does not absorb, only charge transfer or V IV O‐d‐d electronic transitions are observed. Thus, clearly measurable Δ ϵ values can only be recorded in the visible range of the circular dichroism (CD) spectra when there is coordination of donor atoms of the protein to vanadium(IV); otherwise no induced CD‐bands due to charge transfer or d‐d transitions can be measured …”

Argentivorous molecules bearing three aromatic side arms: synthesis of triple-armed cyclens and their complexing property towards Ag+

“…meso-9b was prepared in a similar manner with the synthetic procedure of meso-9a using meso-8a and benzaldehyde-d 6 H, 6.25; D, 4.84; N, 11.21. The thermal conductivity of hydrogen is almost the same as that of deuterium.…”

“…The ligand (0.0151 mmol) in chloroform or dichloromethane (1 mL) was added to the corresponding metal salt (AgPF 6 or AgClO 4 ) (0.0153 mmol) in methanol (1 mL 6 (1 mmol μL −1 ) in CD 3 OD to ligands (5 × 10 −3 mmol/0.65 mL) in CD 2 Cl 2 . UV-vis titration experiments.…”

Vanadium: History, chemistry, interactions with α-amino acids and potential therapeutic applications

“…On the other hand, Table 8 shows other studies done by potentiometry and spectroscopy, involving the complexation of V(IV)O ion with the tripeptides containing L-histidine or L-cysteine (V(IV) O-HisGlyGly, V(IV)O-GlyGlyHis and V(IV)O-GlyGlyCys [118], the coordination of V(IV)O with a tripeptide, which contains salicylic acid and the amino acids L-glycine or L-alanine (V(IV)O-SalGlyAla) [119] as well as the dipeptide formed between salicylic formed with a (NH 2 , N À , N À , COO À ) donor set for HisGlyGly, (NH 2 , N À , N À , N im ) for GlyGlyHis and (NH 2 , N À ,N À , S À ) for GlyGlyCys [118].…”