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Polarographic Behavior of Metal Phytochelatin Complexes
Author(s) -
Scarano Gioacchino,
Morelli Elisabetta
Publication year - 1998
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/(sici)1521-4109(199801)10:1<39::aid-elan39>3.0.co;2-x
Subject(s) - polarography , chemistry , phytochelatin , metal , dropping mercury electrode , phaeodactylum tricornutum , electrochemistry , inorganic chemistry , dissociation (chemistry) , electrode , glutathione , organic chemistry , biology , enzyme , diatom , botany
Abstract The polarographic characteristics of metal‐phytochelatin complexes (Me‐PC) extracted from the marine alga Phaeodactylum tricornutum were investigated by the use of differential pulse polarography (DPP) at dropping mercury electrode (DME). Four metal‐phytochelatin complexes differing for the metal bound, namely Cd‐, Pb‐, Zn‐ and Cu‐PC, were studied, and their polarographic behavior was compared with that of Cd,Zn‐thionein and Zn‐thionein of mammalian origin. The polarographic characteristics of Me‐PC exhibit a dependence on the metal bound to the peptides and on the pH of the solution. Both the organic and inorganic part of Me‐PC are electroactive and give polarographic responses depending on their chemical form in solution. Dissociation and formation processes were investigated. The order of stability of the complexes was K′ Cu−PC > K′ Pb−PC ≥ K′ Cd−PC > K′ Zn−PC . The same electrochemical mechanisms were found to characterize both the polarographic behavior of metallothioneins and metal‐phytochelatin complexes.