How can E.coli GroEL be eliminated from the elution sample?
Proteins can be eluted from the chitin column by virtue of their affinity for a target protein. E. coli host chaperone protein GroEL (with an apparent molecular weight about 57-60 kDa on SDS-PAGE) has been co-purified with the target protein in some cases. This may be indicative of (partial) misfolding of the target protein. Try different temperature inductions to aid in folding (12-37°C). Washing the column with different column buffers prior to the cleavage step may reduce the chances of co-purification of such proteins. High salt concentration (1-2 M), nonionic detergents, and ligand or co-factors (such as ATP or GTP) may be used in the column buffer for different proteins. Washing the column extensively (20 column volumes) with different column buffer prior to the cleavage step may reduce the chances of co-purification of such proteins. High salt concentration (1-2 M), nonionic detergents, and ligand or co-factors (such as ATP or GTP) may be used in the column buffer for different
