Abstract: Alkaline proteins which represent a large part of proteome, remain a great challenge for conventional 2-DE. Fractionation methods can offset the weakness of 2-DE for the analysis of these proteins. In this work, liquid isoelectric focusing(LIEF) and two-dimensional electrophoresis(2-DE) were conbined for the analysis of alkaline proteins from rat liver. Under this strategy, the resolution of alkaline proteins on 2-D gel and reliability of proteins identification by MS were greatly improved, and more low-abundance and highly alkaline proteins were successfully identified compared to 2-DE without LIEF.

Key words: Liquid isoelectric focusing, Two-dimensional electrophoresis, Alkaline protein