Separation of human plasma/serum proteins by capillary isoelectric focusing in the absence of denaturing agents.

Human plasma/serum proteins were separated by capillary isoelectric focusing in the absence of denaturing agents. Proteins focused in a fused silica capillary were mobilized by replacing the catholyte sodium hydroxide to acetic acid. The performance of the separation of human plasma proteins has been examined by changing the duration of the step of isoelectric focusing, carrier ampholyte concentration, and plasma protein concentration. The separation patterns of plasma proteins were compared with those obtained by micro two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) run in the absence of denaturants in order to locate the major plasma proteins on the capillary electropherograms. Using the established electrophoretic conditions and the results of peak identification, proteins in the sera of IgG myeloma patients were analyzed by capillary isoelectric focusing. The advantages of capillary isoelectric focusing in plasma protein analysis compared with 2-D PAGE are discussed.