Short Communication: [CA1]Speciation in the vanadate–alanylhistidine–peroxide system
2000 (English)In: Journal of Inorganic Biochemistry, Vol. 80, no 1-2, 149-151 p.Article in journal (Refereed) Published
The speciation in the quaternary aqueous H+–H2VO4−–H2O2–-α-alanyl--histidine (Ah) system has been determined from quantitative 51V NMR measurements and potentiometric data (glass electrode). The study was performed in 0.150 M Na(Cl) medium at 25 °C. Data were evaluated with the computer program LAKE, which is able to treat combined potentiometric and NMR data. In the ternary H+–H2VO4−–Ah system, two complexes, (H+)p(H2VO4−)q(Ah)r, having (p, q, r) values (0, 1, 1) and (1, 1, 1) (pKa=6.88) explain all data. In the quaternary H+–H2VO4−–H2O2–Ah system, seven complexes were determined in addition to all binary and ternary complexes, four with a V/X/Ah ratio 1:1:1 and three with a ratio 1:2:1 (X=peroxo ligand). VX2Ah2− and VX2Ah− (pKa=8.26) are the main quaternary complexes and predominate in the pH range 5 to 9. Chemical shifts, compositions and formation constants for all the quaternary complexes are given, and equilibrium conditions are illustrated in distribution diagrams.
Place, publisher, year, edition, pages
2000. Vol. 80, no 1-2, 149-151 p.
Vanadium; 51V NMR; Dipeptide complexes; Peroxovanadium complexes
IdentifiersURN: urn:nbn:se:umu:diva-8967DOI: doi:10.1016/S0162-0134(00)00023-4OAI: oai:DiVA.org:umu-8967DiVA: diva2:148638