Rapid Purification of Recombinant Antibody Fragments for Catalysis Screening

A subpopulation of antibodies with high affinity for the substrate ground state is also capable of chemical catalysis (1 ). However, high turnover by catalysts is dependent on efficient binding to the transition state, not the ground state. Direct screening for catalysis may permit isolation of more efficient antibody catalysts, since this approach obviates the requirement for strong binding to substrate ground states (or presumed transition state analogs). To this end, we have developed methods to purify recombinant antibody fragments rapidly, followed by measurement of their catalytic activity using peptide-methylcoumarinamide conjugates or radiolabeled peptides as substrates.