Fractionation by size (molecular weight) is an effective enrichment strategy for studies of protein families and posttranslational modifications, because the sizes of these proteins tend to be similar.

The Model 491 prep cell and the mini prep cell:

• Allow resolution of proteins differing in molecular weight by as little as 2%
• Separate up to 500 mg of total protein
• Can be used as a complementary separation strategy to 2-D gels as well as for downstream protein purification

The Model 491 prep cell has a sample capacity of 1–500 mg/0.5–15 ml, while the mini prep cell has a sample capacity of 0.5–1,000 µg/50–500 µl.