Investigation of complexation of immobilized metallothionein with Zn(II) and Cd(II) ions using piezoelectric crystals.
The aim of this study is to investigate complexation of metallothionein (MT) with cadmium and zinc ions. An oligopeptide (i.e. Lys-Cys-Thr-Cys-Cys-Ala), a fragment of MT was covalently immobilized onto piezoelectric crystals, which were first treated with ethylene diamine plasma in a glow-discharge apparatus, and then were chemically reacted with glutaraldehyde. Complexation of the immobilized MT with Zn(II) and Cd(II) ions in aqueous media was followed by recording the changes of the frequency shifts of the piezoelectric quartz crystals. The amount of Cd(II) ions interacted with the immobilized MT molecules was the highest at pH 7.4, and decreased with an increase in the pH of the medium, in parallel to the decrease in the amount of immobilized MT. The number of Zn(II) ions interacted with the immobilized MT molecules was higher than the number of Cd(II) ions when the adsorption was from solutions containing a single-metal ion with the same ion concentrations. In consecutive adsorption studies, we observed that the type of metal ions used in the first interaction is important. These experiments showed also that there is an exchange between the metal ions, and competition provokes adsorption of both ions due to synergistic-antagonistic effects.
Saber
Reza
R
Department of Chemical Engineering and Bioengineering Division, Hacettepe University, 06532 Beytepe, Ankara, Turkey.
Pişkin
Erhan
E
D000327:Adsorption; D002104:Cadmium / Q000032:analysis* / Q000737:chemistry; D003460:Crystallization / Q000379:methods*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D008668:Metallothionein / Q000032:analysis* / Q000737:chemistry; D011485:Protein Binding; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers; D015032:Zinc / Q000032:analysis* / Q000737:chemistry
D002104:Cadmium; D008668:Metallothionein; D015032:Zinc