Catalog number: SBB-UP0013,10 mgUbiquitin, human recombinant, is a small (8.5 kDa) regulatory protein that has been found in almost all tissues of eukaryotic organisms. The addition of ubiquitin to a substrate protein is called ubiquitination or ubiquitylation. Ubiquitination can affect proteins in many ways: it can signal for their degradation via the proteasome, alter their cellular location, affect their activity, and promote or prevent protein interactions. [1][2][3][4][5]