Submitted to: Protein Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2005
Publication Date: 11/14/2005
Citation: Mao, Y., Lai, C., Vogtentanz, G., Schmidt, B., Day, T., Miller, J., Brandon, D.L., Chen, D. 2005. MONOCLONAL ANTIBODIES AGAINST SOYBEAN BOWMAN-BIRK INHIBITOR RECOGNIZE THE PROTEASE-REACTIVE LOOPS. Protein Journal. 24(5):275-282. Interpretive Summary: Both adverse nutritional effects as well as health-promoting effects have been attributed to the consumption of the Bowman-Birk inhibitor, a protein found in soybeans. We previously developed monoclonal antibody-based immunoassays to measure the protein in soy foods. Two of these antibodies were further characterized in this study undertaken in collaboration with Genencor International. The results show that the antibodies bind to the enzyme-binding regions of this inhibitor and that the antibodies can change the activity of the Bowman-Birk inhibitor. This information could be used to help elucidate the mechanisms by which Bowman-Birk inhibitor inhibits tumor formation.
Technical Abstract: Monoclonal antibodies against soybean Bowman-Birk protease inhibitor (BBI) have been generated and used as agents to detect and quantify BBI in foods, soybean germplasm, and animal tissues and fluids. The purpose of this study was to determine the recognition sites of two monoclonal antibodies to BBI (mAb 238 and mAb 217) in relation to the protease-inhibitory sites of BBI. The results showed that 1) the binding of mAb 238 can be blocked by trypsin and that of mAb 217 by chymotrypsin; 2) the trypsin or chymotrypsin inhibitory activities of BBI are blocked by mAb 238 or mAb 217, respectively; and 3) mAb 238 failed to recognize a tryptic loop mutant BBI variant and mAb 217 was unable to bind a chymotryptic loop mutant BBI variant. These findings demonstrate that the epitopes recognized by mAb 238 and mAb 217 reside, at least in part, in the tryptic and chymotryptic loops of BBI, respectively.