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Optimization of affinity capillary electrophoresis for routine investigations of protein–metal ion interactions
Author(s) -
Alhazmi Hassan A.,
Deeb Sami El,
Nachbar Markus,
Redweik Sabine,
Albishri Hassan M.,
ElHady Deia Abd,
Wätzig Hermann
Publication year - 2015
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201500182
Subject(s) - capillary electrophoresis , capillary action , chemistry , chromatography , electrophoresis , analytical chemistry (journal) , affinity electrophoresis , ethylenediaminetetraacetic acid , metal , metal ions in aqueous solution , chelation , materials science , inorganic chemistry , affinity chromatography , biochemistry , organic chemistry , composite material , enzyme
To facilitate the implementation of affinity capillary electrophoresis into routine binding screening studies of proteins with metal ions, method acceleration, transfer and precision improvement were investigated. Affinity capillary electrophoresis was accelerated by using shorter capillaries, employing lower sample concentrations and smaller injection volumes. Intra‐ and inter‐instrument method transfers were investigated considering the temperature setting of the capillary cooling system. For intra‐instrument method transfer, similar results were obtained when transferring a method from a long (62 cm) to a short (31 cm) capillary. The analysis time was reduced from 9 to 4 min. In case of inter‐instrument method transfer, interaction results showed small variation on the capillary electrophoresis instrument with inefficient capillary cooling system. Binding measurement precision was enhanced by slightly pushing the sample above the beginning of the capillary. Changing the buffer vials after each 30 runs and employing extra flushing after each 60 subsequent runs further enhanced the precision. The use of 0.1 molar ethylenediaminetetraacetic acid in the rinsing solution successfully desorbs the remaining metal ions from the capillary wall. Excellent precision for apparent mobility ratio measurements was achieved for different protein–metal ion interactions (relative standard deviation of 0.16–0.89%, 15 series, 12 runs for each).