Rapid screening of a large number of immobilized textile dyes for the purification of proteins: use of penicillin-binding protein 4 of Escherichia coli as a model enzyme.

A rapid method for screening the affinity of proteins to dye-modified resins is described. Performing the binding and elution of the protein extracts in a batch-wise manner and eluting the bound proteins with SDS-PAGE denaturation buffer speed up the screening process and allow the analysis of large collections of dyes. Penicillin-binding protein 4 of Escherichia coli was used as a model enzyme to determine the influences of pH, metal ions, and ionic strength (0 to 500 mM NaCl) on its binding behavior using a collection of 98 dye-affinity resins.