Active, full-length human 2'-5' oligoadenylate synthetase 1 enzyme, His-tagged protein expressed and purified from E.coli. The enzyme has been thoroughly validated with Transcreener 2-5A OAS Activity Assays. For specific activity, please refer to the Certificate of Analysis for each individual enzyme lot. Purity is >95% in a 20 mM Tris-HCl pH 8.0, 10% glycerol, 1 mM DTT buffer composition. Currently used with the Transcreener assay at a concentration between 3 and 16 nM.