Improved separation of metallothionein isoforms by the presence of cyclodextrin in capillary zone electrophoresis

Abstract

Capillary zone electrophoresis (CZE) with cyclodextrin (CD) in the polyacrylamide-coated capillary was used to study metallothionein (MT) forms in the horse kidney preparation produced commercially by Sigma. It is known that CDs form complexes with hydrophobic amino acids. The results show that the presence of CD improves the separability of the various MT forms, including the MT-IA and the MT-IB forms, metallothionein aggregates, as well as the so far unidentified a and b forms. This was true both below and above the isoelectric points (pIs), although the migration times were somewhat longer at increasing CD concentrations for runs at constant voltage than with constant current.

Analytical Methods for Metallothionein Detection

“…This paper is paying special attention to the elimination of the wall adsorption by polyacrylamide coating of inner capillary walls which is often used method for MT separation [124,125]. Another attempt of MT isoforms separation improvement by addition of cyclodextrines was done by Wilhelmsen et al [126]. The results showed that the presence of cyclodextrines improves significantly the separation efficiency of the various MT forms from horse kidney both below and above isoelectric point of MTs.…”

Stereoselectivity of the Hydrogen‐Atom Transfer in Benzophenone–Tyrosine Dyads: An Intramolecular Kinetic Solvent Effect

“…CE coupled with MS, CE‐ESI‐MS, was applied to separate and characterize rabbit liver MTs, which are complex mixtures of protein isoforms 22, 23. CE was used for the analysis of MT isoforms 24, 25, stability 26, 27, and for studying MT oligomerization 21, 28.…”

Element Speciation Analysis Using Capillary Electrophoresis: Twenty Years of Development and Applications

“…Other approaches to regulating electrolyte composition in order to complete the resolution of complex mixtures or analytes that differ only slightly in electrophoretic mobility include the following: (i) varying the nature of the electrolyte buffer, (ii) increasing the concentration of the counterion (to evolve ion association with the separand), and (iii) addition of an organic solvent such as methanol, ,,,,− ,,, acetonitrile, ,, ethanol, or 1-butanol . In the case of hydrophobic or zwitterionic analytes, micellar, ,,,,, nonaqueous, ,, or cyclodextrin-modified , electrolytes can all be utilized for improving separability. Research has also been devoted to the enantioselective separation of metal–ligand complexes using electrolytes containing chiral additives, such as various tartrate derivatives, cyclodextrins, synthetic DNA polynucleotide, sodium cholate or other bile salt surfactants .…”

“…This approach was used in the characterizing of Zn(II) complexes with carbonic anhydrases from red blood cells and quantifying the protein adducts of ruthenium(III)-based drugs, , respectively. Similarly, polyacrylamide-coated capillaries have paved the way in attaining the goal of clarifying the properties of MT isoforms, , including those existing in liver or pancreas cytosol, ,,,,, without the risk of nonspecific adsorption of the analytes.…”