title: On the possibility of applying noncovalent dyes for protein labeling in isoelectric focusing.
abstract: Noncovalent fluorescent dyes are widely used for protein quantification and postcolumn detection in electrophoretic separations and recently some attempts to separate the precolumn labeled proteins using isoelectric focusing (IEF) have been made. In the present study, the possibility of applying the technique of protein labeling with noncovalent dyes for IEF is investigated. We found that fluorescent signal emitted by NanoOrange dye increases essentially in presence of carrier ampholyte (CA) components, which makes problematic a reliable protein detection in CA environment. Since in an isoelectric focusing mode the CA species are present in much greater concentration than the concentrations of fractionated proteins, the method of protein labeling with NanoOrange is not suitable for precolumn labeling and cannot be used for CA-IEF, at least without more detailed study of the dye-protein interaction mechanism.
authors.affiliation: VPB, Purdue University, 625 Harrison Street, West Lafayette, IN 47907, USA. stoyanov@purdue.edu
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Stoyanov
authors.forename: Z Hugh
authors.initials: ZH
authors.lastname: Fan
authors.forename: Champak
authors.initials: C
authors.lastname: Das
authors.forename: Hossein
authors.initials: H
authors.lastname: Ahmadzadeh
authors.forename: Qian
authors.initials: Q
authors.lastname: Mei
authors.forename: Sulma
authors.initials: S
authors.lastname: Mohammed
mesh_terms: D000665:Ampholyte Mixtures / Q000737:chemistry; D004572:Electrolysis; D005456:Fluorescent Dyes / Q000737:chemistry*; D007525:Isoelectric Focusing / Q000379:methods*; D009930:Organic Chemicals / Q000737:chemistry; D011506:Proteins / Q000032:analysis*
chemical_list: D000665:Ampholyte Mixtures; D005456:Fluorescent Dyes; C433144:NanoOrange; D009930:Organic Chemicals; D011506:Proteins