Ubiquitin is a small, evolutionarily conserved eukaryotic protein that can be attached to a wide variety of intracellular proteins including itself. Covalent attachment of ubiquitin to other proteins serves various functions, but its major role is to target cellular proteins for destruction. Cellular components that activate, transfer, remove, or simply recognize ubiquitin number in the hundreds, perhaps even in the thousands. In light of this complexity the ubiquitin pathway is ideal for a systems biology approach. Ubiquitin (Ub) plays a very important role in regulated non-lysosomal ATP dependent protein degradation. The protein to be degraded is conjugated to Ub and the ubiquinated protein is then selectively degraded by a 26S complex, multicatalytic cytosolic and nuclear protease termed proteasome. The Ub-proteasome proteolytic pathway, which is a complex process, is implicated to be of great importance for regulating numerous cellular processes.
Ubiquitin is a highly conserved 76 amino acid protein expressed in all eukariotes. Ub is found either in free form or conjugated to proteins as monomer or as chain of ubiquitin molecules. The most well characterized consequence of polyubiquitination is substrate degradation, while mono-ubiquitinated proteins are not degraded. Ubiquitin attachment to protein substrate is a complex process involving an ubiquitin activating enzyme (E1), an ubiquitin conjugating enzyme (E2) and an ubiquitin protein ligase (E3). The first ubiquitin moiety is transferred to the e-NH2 group of a Lys residue of the protein substrate to generate an isopeptide bond. In successive reactions, a poly ubiquitin chain is synthesized by processive transfer of additional activated moieties to Lys48 of the previously conjugated ubiquitin molecule. Ubiquitin K48R prevents the formation of poly ubiquitin chains via Lys48 linkages with mono ubiquitin molecules, avoiding the degradation of protein substrates. Recombinant human ubiquitin featuring a Lys 48 to Arg48 mutation, useful for the reduction of poly-Ub chain length and conjugation rates.
Storage & Stability:
Store vial at -20 degrees C to -80 degrees C. When stored at the recommended temperature, this protein is stable for 12 months. Please avoid freeze-thaw cycles.