Characterization of the interactions between immobilized parathion and thecorresponding recombinant scFv antibody using a piezoelectric biosensor

A piezoelectric quartz crystal sensor with immobilized parathion was used f or real-time kinetic characterization of the interactions with recombinant anti-parathion single chain Fv antibody IFRN AA01 (scFv). Parathion,was lin ked to the sensor gold electrodes modified with a self-assembled layer of a minothiophenol using either bovine serum albumin (BSA) or dextran as spacer molecules. The kinetic dissociation rate constant k(d) was 8 x 10(-4) s(-1 ) for both types of sensors, and the association rate constants k(d) were 5 90 and 260 mol(-1) l s(-1) for BSA and dextran-linked parathion, respective ly. The regeneration of BSA-parathion coated crystals was not successful, h owever. Those crystals with bound scFv were used to study the formation of scFv dimers. Dextran-parathion modified crystals were successfully regenera ted using proteinase K. The affinity of scFv to dextran-parathion was 50 x lower when compared with the affinity of the anti-parathion monoclonal anti body (IgG, IFRN 1701) the sequence of which served for production of scFv.