Streptavidin conjugated to reporter enzyme molecules for use in blotting and in situ hybridization applications. High specificity reagents. The conjugation of horseradish peroxidase and streptavidin is achieved using the periodate coupling method described by Nakane and coworkers. This product is sold on the basis of titer in an ELISA and performance in a Western blot. As a result the final protein concentration of the conjugate (RPN 1231) will vary only minimally between batches. Biotin is linked via a spacer arm to horseradish peroxidase under conditions that preserve high enzyme activity and give a high degree of biotinylation as judged by its ability to bind to streptavidin. Excess labeling reagent is removed by gel filtration. Biotinylated enzyme is added to streptavidin to form complexes. The complex is optimized to produce an excellent combination of titer and sensitivity for binding to biotinylated protein. This product is sold on the basis of titer determined in a standard assay. As a result the final protein concentration of the complex may vary minimally between batches.
