Small regulatory protein tagging substrates for proteasomal degradation, controlling protein turnover, DNA repair, and cell signalling. Recombinant human tag free ubiquitin (1-76) protein was expressed in E. coli cells. Molecular weight 10 kDa. Supplied as sterile 20 mM Tris-HCl, pH 7.0, 150 mM NaCl, 0.1 mM EDTA, 1 mM DTT, 10-25% glycerol. Store product at –70°C. For optimal storage, aliquot target into smaller quantities. Avoid repeated handling and multiple freeze/thaw cycles.