Figure 6. Determination of the binding-competent fraction.

The fraction of a Fab solution competent to bind to its antigen was determined by serial immunodepletion of the Fab. A₂₈₀ of the starting stock was measured and then exposed to antigen immobilized on sepharose beads for 10 min. Beads were removed by centrifugation and the amount of protein remaining in the supernatant was determined by A₂₈₀. This procedure was repeated until no further reduction in A₂₈₀ was observed. The competent fraction was determined by 1- (A₂₈₀ final/A₂₈₀ initial).