Chelation Study of Captopril with Cd2+ and Pb2+
Mohammad Joshaghani, M.B. Gholivand and A.R. Mosavat
DOI : 10.3844/ajbbsp.2008.245.249
American Journal of Biochemistry and Biotechnology
Volume 4, Issue 3
The protonation constants of Captopril, (1-(3-mercapto-2-(S)-methyl-1-oxopropyl)-S(L) proline, (CPL) and stabilities of its two divalent metal ions Cd(II) and Pb(II) were determined potentiometrically in two different metal to ligand ratio 1:1 and 1:2 systems and in water and methanol-water binary mixtures using the computer Best program. Two protonation constants were obtained which were assigned to the carboxylic and thiol groups. All protonation and stability constants increased with decreasing the dielectric constant on going from the pure water to the binary mixtures. An excellent similarity in stabilities of studied metal ions strongly suggests that both metal ions are coordinated by CPL in a same manner through the thiol group.
© 2008 Mohammad Joshaghani, M.B. Gholivand and A.R. Mosavat. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.