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Parallel isoelectric focusing chip
Author(s) -
Zilberstein Gleb,
Korol Leonid,
Bukshpan Shmuel,
Baskin Emanuil
Publication year - 2004
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200300794
Subject(s) - isoelectric focusing , chromatography , chip , isoelectric point , chemistry , computational biology , computer science , biology , biochemistry , telecommunications , enzyme
Fast isoelectric focusing (IEF) is becoming a key method in modern protein analysis. We report here the theory and experimental results of new parallel isoelectric devices (PID) for fast IEF. The main separation tool of any PID is a dielectric membrane with conducting channels filled by immobiline gels of varying pH. The pH value of the surrounding aqueous solution is not equal to the pH of any of the channels. The membrane is held perpendicular to the applied electric field. Proteins are collected (trapped) in the channels whose pH values are equal to the p I of the proteins. The fast particle transport between different channels takes place due to convection in the aqueous solution. We developed a mathematical model for PID. Experiment duration is shown to be proportional to the number of different bands N (the peak capacity in standard IEF) in contrast with N 2 for usual IEF devices. This model was validated with experimental results. Parallel IEF accelerates the fractionation of proteins by their p I values (down to several minutes) allowing a more desirable collection efficiency to be achieved. The main theoretical limitation of PID resolution is the sensitivity of proteins to pH change due to the Coulomb blockade effect. The existence of a minimal pH change δpH min for each type of protein is shown: δpH min ∼ r −1 for globular molecules with radius r.