title: Steady-state protein focusing in carrier ampholyte based isoelectric focusing: Part I-Analytical solution.
abstract: The determination of an analytical solution to find the steady-state protein concentration distribution in IEF is very challenging due to the nonlinear coupling between mass and charge conservation equations. In this study, approximate analytical solutions are obtained for steady-state protein distribution in carrier ampholyte based IEF. Similar to the work of Svensson, the final concentration profile for proteins is assumed to be Gaussian, but appropriate expressions are presented in order to obtain the effective electric field and pH gradient in the focused protein band region. Analytical results are found from iterative solutions of a system of coupled algebraic equations using only several iterations for IEF separation of three plasma proteins: albumin, cardiac troponin I, and hemoglobin. The analytical results are compared with numerically predicted results for IEF, showing excellent agreement. Analytically obtained electric field and ionic conductivity distributions show significant deviation from their nominal values, which is essential in finding the protein focusing behavior at isoelectric points. These analytical solutions can be used to determine steady-state protein concentration distribution for experiment design of IEF considering any number of proteins and ampholytes. Moreover, the model presented herein can be used to find the conductivity, electric field, and pH field.
authors.affiliation: School of Mechanical Engineering, Yeungnam University, Gyeongsan, Gyeonsanbukdo, South Korea.
authors.forename: Jaesool
authors.initials: J
authors.lastname: Shim
authors.affiliation: School of Mechanical Engineering, Yeungnam University, Gyeongsan, Gyeonsanbukdo, South Korea.
authors.forename: Kisoo
authors.initials: K
authors.lastname: Yoo
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, WA, USA.
authors.forename: Prashanta
authors.initials: P
authors.lastname: Dutta
mesh_terms: D000665:Ampholyte Mixtures / Q000737:chemistry*; D001798:Blood Proteins / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D004553:Electric Conductivity; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing / Q000379:methods*
chemical_list: D000665:Ampholyte Mixtures; D001798:Blood Proteins
keywords: Analytical results; Carrier ampholytes; IEF; Protein