69212  S•Tag™ Rapid Assay Kit

Sensitive colorimetric quantification of S•Tag fusion proteins

With the S•Tag™ Rapid Assay, a sample is added to a buffer containing the ribonuclease substrate poly(C). The reaction is started by adding purified S-protein. After a 5-minute incubation, the reaction is stopped with trichloroacetic acid. The resulting precipitate is removed by centrifugation. Activity is measured by reading the absorbance of the supernatant at 280 nm, which increases as the poly(C) is broken down into acid-soluble nucleotides by the enzyme. By comparing the results with a known S-peptide standard included in the kit, the molar concentration of target protein in the sample can be determined. As little as 20 fmol of target protein can be detected in a 5-minute incubation with the S•Tag Rapid Assay. Samples can be crude extracts prepared with BugBuster®, PopCulture®, CytoBuster™, or Reportasol™ reagents; SDS; subcellular fractions; translation reactions; or purified proteins. In most applications, there is negligible interference from endogenous RNases.

The S•Tag Rapid Assay Kit includes a set of matched reagents designed to perform 100 standard assays.