title: Optimization of affinity capillary electrophoresis for routine investigations of protein-metal ion interactions.
abstract: 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).
authors.affiliation: Institute of Medicinal and Pharmaceutical Chemistry, TU Braunschweig, Braunschweig, Germany.|Department of Pharmaceutical Chemistry, College of pharmacy, Jazan University, Jazan, Saudi Arabia.
authors.forename: Hassan A
authors.initials: HA
authors.lastname: Alhazmi
authors.affiliation: Institute of Medicinal and Pharmaceutical Chemistry, TU Braunschweig, Braunschweig, Germany.
authors.forename: Sami El
authors.initials: SE
authors.lastname: Deeb
authors.affiliation: Institute of Medicinal and Pharmaceutical Chemistry, TU Braunschweig, Braunschweig, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Nachbar
authors.affiliation: Institute of Medicinal and Pharmaceutical Chemistry, TU Braunschweig, Braunschweig, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Redweik
authors.affiliation: Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Hassan M
authors.initials: HM
authors.lastname: Albishri
authors.affiliation: Chemistry Department, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia.|Chemistry Department, Faculty of Science, Assiut University, Assiut, Egypt.
authors.forename: Deia Abd
authors.initials: DA
authors.lastname: El-Hady
authors.affiliation: Institute of Medicinal and Pharmaceutical Chemistry, TU Braunschweig, Braunschweig, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Wätzig
mesh_terms: D000818:Animals; D001464:Barium / Q000737:chemistry*; D002417:Cattle; D002846:Chromatography, Affinity; D019075:Electrophoresis, Capillary; D006801:Humans; D007782:Lactoglobulins / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D010047:Ovalbumin / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*
chemical_list: D007782:Lactoglobulins; D012709:Serum Albumin; D001464:Barium; D009532:Nickel; D010047:Ovalbumin
keywords: Affinity capillary electrophoresis; Method transfer; Protein-metal interaction; Sample pushing; Short capillaries