Cadmium binding in mixtures of phytochelatins and their fragments: a voltammetric study assisted by multivariate curve resolution and mass spectrometry.
Phytochelatins (PC(n), (gamma-Glu-Cys)(n)Gly) are cysteine-rich peptides synthesized by plants which are involved in metal bioregulation and phytoremediation. Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) is applied to voltammetric data obtained from the analysis of the competitive binding of Cys or Cys-Gly with PC(2) or PC(3) by Cd(2+). The displacements between ligands, the chain length dependence on the competitive binding to PC(n) and the possible existence of mixed ligand metal-complexes are investigated. The shape analysis of the resulting pure voltammograms and concentration profiles of the components resolved by MCR-ALS suggests that ligands containing more thiol groups are able to displace the shorter chain ligands from their metal complexes, whereas the opposite does not happen. Electrochemical results are compared with ESI-MS measurements.
Gusmão
Rui
R
Departament de Química Analítica, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1 - 11, E - 08028, Barcelona, Spain. miquelestebanc@ub.edu
Ariño
Cristina
C
Díaz-Cruz
José Manuel
JM
Esteban
Miquel
M
D002104:Cadmium / Q000032:analysis* / Q000737:chemistry; D056831:Coordination Complexes / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D054811:Phytochelatins / Q000737:chemistry*; D011485:Protein Binding; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013438:Sulfhydryl Compounds / Q000737:chemistry
D056831:Coordination Complexes; D013438:Sulfhydryl Compounds; D002104:Cadmium; D054811:Phytochelatins