Bio-Rad Rotofor® and Mini Rotofor Cells - Manual (Page 44)

13.1 Introduction
We report here a new preparative two-dimensional (2-D) electrophoresis system
for purification of proteins. The system is based on the same principles of isoelectric
focusing and gel electrophoresis as analytical two-dimensional electrophoresis. The
procedure, which combines the Rotofor
® preparative isoelectric focusing (IEF) cell
and the new Model 491 Prep Cell for preparative gel electrophoresis (PAGE), is
applicable to a wide range of biological samples. This preparative 2-D system is
designed to purify individual proteins from crude, complex mixtures for detailed
compositional analysis and antibody production and is especially advantageous for
isolating proteins present in low concentrations in the specimen.
Fig. 1. Analytical 2-D gel map of whole human plasma. This silver stained second-dimension gel
demonstrates the complexity of the starting sample. The positions of the glycosylation-induced isoforms
of Apo J, and the uncharacterized 49 kd protein of interest, purified by preparative 2-D electrophoresis,
are indicated.
Analytical two-dimensional (2-D) gel electrophoresis is now a routine procedure
for reproducible separation of proteins in complex biological samples 1,2,3 . Over
3000 tissue proteins and more than 1000 plasma proteins can be resolved by this
method. However, analytical 2-D electrophoresis procedures are incapable of sup-
plying sufficient amounts of low abundance proteins for further characterization. It
has been necessary to recover proteins from several gels for sequence analysis
4 ,
assay, or antibody production 5 .
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