A convenient gel holder for preparative electrophoretic separation of aggregated bacterial proteins

A simple custom-made gel holder for preparative SDS-PAGE to separate aggregated bacterial antigens is described. The gel holder fits easily into commercially available gel electrophoresis apparatus and proteins or peptides are collected in a stream of distilled water through a channel in the gel. The performance of the device was illustrated by the successful separation and purification of fragments of aggregated Streptococcus equi M protein and of Erysipelothrix rhusiopathiae protective antigens. Yields of up to 1.2 mg per run were obtained. The purified proteins retained immunological reactivity and were of sufficient purity for amino acid compositional and sequence analysis.