Submitted on October 15, 2001
Revised on October 16, 2001
Accepted on October 15, 2001
Fully automated two-dimensional capillary electrophoresis for high-sensitivity protein analysis
David A. Michels, Shen Hu, Regine M. Schoenherr, Michael J. Eggertson, and Norman J. Dovichi
University of Washington, Seattle, WA 98195-1700
Corresponding Author: dovichi{at}chem.washington.edu
We report a system for automated protein analysis. In the system, proteins are labeled with the fluorogenic reagent 3-(2-furoyl)quinoline-2-carboxaldehyde (FQ), which reacts with lysine residues and creates a highly fluorescent product. These labeled proteins are analyzed by submicellar capil-lary electrophoresis at pH 7.5 to perform a first dimension separation. Once the first components migrate from the capillary, a fraction is transferred to a second dimension capillary, where electro-phoresis is performed at pH 11.1 to further separate the proteins. Laser-induced fluorescence is used as an ultrasensitive detector of the separated proteins. Successive fractions are transferred from the first dimension capillary to the second dimension capillary for further separation to generate, in serial fashion, a two-dimensional electropherogram. The transfer of fractions is computer controlled; there is no operator intervention once the sample has been injected. Zeptomoles of labeled proteins are detected, providing exquisite sensitivity.