Simultaneous metal chelate affinity purification and endotoxin clearance of recombinant antibody fragments.

Endotoxins are frequent contaminants of recombinant proteins produced in Escherichia coli. Due to their adverse effects, endotoxins have to be removed from recombinant proteins prior their use in cell-based assays or parenteral application. Reduction of endotoxin to less than 10 EU mg(-1) is, however, one of the most problematic steps during protein purification from E.