Species Reactivity: humanSource: E.coliFormula: 50 mM HEPES pH 7.5, 150 mM sodium chloride, 2 mM dithiothreitol, 10% glycerolConcentration: 0.5 mg/mlMolecular Weight: ~17.7 kDaProtein Sequence: Accession number: P62987. For full protein sequence information download the Certificate of Analysis pdf.Quality Control Protein Identification: The linkage type (linear) was confirmed by tandem mass spectrometry.Quality Control Activity: Di-ubiquitin cleavage assay: The capacity of the di-ubiquitin substrate to be cleaved was tested using a promiscuous- with respect to ubiquitin linkage specificity- deubiquitylase (GST-USP2). Incubation of the di-ubiquitin for 1 hour at 37 °C was compared either in the absence (Lane 2) or presence (Lane 3) of GST-USP2. The reaction products were compared alongside two control samples containing either mono-ubiquitin (Lane 4) or GST-USP2 (Lane 5) only. Cleavage of the di-ubiquitin and generation of mono-ubiquitin was determined by running reactions on a 4-12%­SDS-PAGE gel and staining with InstantBlueâ„¢ (Lane 1; molecular weight markers).