Zenon technology depends on the modular nature of antibody molecules. The reagents are labeling molecules—dyes, haptens, or enzymes—conjugated to protein fragments that contain the antigen-binding variable domain from goat-antimouse IgG1 antibodies. These fragments—called Fab fragments—recognize the target antibody's constant region (Fc). Users mix the Zenon reagent for five minutes with the primary antibody to be labeled. Once the excess reagent is removed by a five-minute incubation with nonspecific mouse IgG1, the immune complexes are ready for use in immunoassays.
Zenon's Fc-specificity offers two benefits. First, scientists need not purify the target antibody away from other proteins or amine-containing buffers prior to labeling. In addition, the reagent will not obscure the primary antibody's antigen-recognition sites. Chip Walker, Molecular Probes' life science products manager, adds that the technology is also both faster and more efficient than chemical labeling protocols. Instead of using 100 ug of primary antibody, as chemical reactions do, Zenon ...
