title: Protocol of capillary isoelectric focusing to separate extremely acidic and basic proteins.
abstract: A new set-up was constructed for capillary isoelectric focusing (CIEF) involving a sampling capillary as a bypass fixed to the separation capillary. Sample solutions were subjected to a previously established pH gradient from the sample capillary. Besides performing conventional CIEF, the separation of ampholytic compounds with isoelectric points (p/s) beyond the pH gradient was carried out on this system. This method was termed as pH gradient driven electrophoresis (PGDE) and the basic mathematical expressions were derived to express the dynamic fundamentals. Proteins such as lysozyme, cytochrome C, and pepsin with p/s higher than 10 or below 3 were separated in a pH gradient provided by Pharmalyte (pH 3-10). Finally, this protocol convincingly exhibited its potential in the separation of a solution of chicken egg white.
authors.affiliation: Department of Biotechnology, National Chromatographic R & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116011, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Yang
authors.forename: Weibing
authors.initials: W
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Jicheng
authors.initials: J
authors.lastname: Duan
authors.forename: Yukui
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001699:Biometry; D045304:Cytochromes c / Q000737:chemistry / Q000302:isolation & purification; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D009113:Muramidase / Q000737:chemistry / Q000302:isolation & purification; D010434:Pepsin A / Q000737:chemistry / Q000302:isolation & purification; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D011506:Proteins; D045304:Cytochromes c; D009113:Muramidase; D010434:Pepsin A