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In order to obtain a better understanding of the electrochemical behaviour of the metallothionein (MT), the peptidic fragment Lys-Cys-Thr-Cys-Cys-Ala [56-61] MT I (FT) compound constitutive of the proteic structure has been studied. Under the experimental conditions, with a low concentration of the substance (<5 x 1.0 E-5 M) and the use of a dropping mercury electrode, a diffusion controlled mechanism is suggested for the electrochemical behaviour of FT. In this case the mercury electrode itself is involved in the charge transfer step and the polarographic response is attributed to the oxidation of the mercury electrode in the presence of the chelating agent FT. The influence of the pH of the solution on the behaviour of FT was investigated using DC and DPP methods. The variation of i(l), i(p) and E(p) with pH was determined. From these results the apparent acid-base dissociation constant of the FT was evaluated, corresponding to the dissociation of protons from the thiol groups. Likewise the apparent stability constants of the Hg-FT were estimated as a function of the pH. It was assumed that the main complex of Hg-FT possessed a stoichiometry of 1:1 but it is probable that two or more different complexes coexisted.

Additional information

Authors: MENDIETA J, JRC Geel (BE);RODRIGUEZ A, JRC Geel (BE);CHIVOT J, CEA, CEN Fontenay-aux-Roses (FR);MUÑOZ A, University of Wisconsin, Department of Chemistry, Milwaukee (US)
Bibliographic Reference: Article: Electroanalysis, Vol. 7 (1995) No. 7, pp. 663-668
Record Number: 199511420 / Last updated on: 1995-11-03
Original language: en
Available languages: en