K48-linked Tetra-Ubiquitin (human) (rec.) (untagged)

The array of cellular processes initiated and regulated by ubiquitin has been partially explained by the structural diversity of differently linked ubiquitin chains. In a ubiquitin chain, ubiquitin moieties can be conjugated through one of their lysine residues (K6, K11, K27, K29, K33, K48 and K63) or the N-terminal methionine residue (M1), offering countless possibilities to assemble a specific polymer. Ubiquitin molecules can also be modified by other post-translational modifications, including acetylation and phosphorylation, adding another layer of ubiquitin signal regulation and diversification. K48-polyubiquitin chains are the most abundant linkage in cells and thought to be the major signal for proteasome-mediated degradation. Quantitative MS analyses of intracellular ubiquitin linkages reveled K48-polyubiquitin linkages rapidly accumulate when cells are treated with the proteasome inhibitor MG132. This protein is formed with wild-type human recombinant ubiquitin and linkage-specific enzymes. Ideal for investigating ubiquitin-binding proteins and as substrates for ubiquitin-specific isopeptidases. Reaction conditions will need to be optimized for each specific application.