Ubiqutin (Ub) is initially produced as a 229-a.a. Polyubiquitin-B (UniProt P0CG47) precursor protein encoded by the UBB gene (Gene ID 7314) or a 685-a.a. Polyubiquitin-C precursor protein (UniProt P0CG48) encoded by the UBC gene (Gene ID 7316) in human. Posttranslational cleavages yield multiple copies of idential 76-amino acid ubiquitin (also known as high mobility group nonhistone protein HMG-20) molecules. Ub is involved in one of the most common post-translational modifications (PTMs) of cellular proteins, where Ub is linked covalently via its carboxyl terminus (Gly76) to usually Lys residues in target proteins. A given target Lys residue can be linked to one single Ub molecule (monoubiquitylated) or to a chain of Ub molecules (polyubiquitylated). In a polyUb chain, Ub molecules can be linked through one of the seven Lys residues (K6, K11, K27, K29, K33, K48, and K63) or through the Ub N-terminus Met1 residue (which generates linear chains). Lys-C is an endopeptidase that cleaves proteins on the C-terminal side of unmodified lysine residues, but not Ub-modified Lysine residues, generating peptide fragments with a C-terminus Lysine and internal Lysine residue(s) linked to a Ub C-terminal remnant (as a result of Lys-C cleavage between Ub K63 and E64). Antiboides that specifically target this Ub C-terminal remnant (i.e. E64 to Gly76 or E48 to Gly76 if K63 is ubiquitinated in a polyUb chain) are compatible with the patented UbiSite methodology for Lysine ubiquitination site determination developed by the laboratory of Dr. Blagoy Blagoev at University of Southern Denmark. Such antibodies can isolate Lys-C digested fragments with Ub modification site(s), followed by further trypsin digestion to leave only Gly75-Gly76 covalently linked to the modified Lysine on the isolated peptide fragments prior to Mass spectroscopy (MS) analysis to determine the Lysine modification site(s).
Synonyms: Polyubiquitin-B, Polyubiquitin-C, Ubiquitin, Ub
Application: Western Blotting Analysis: 1.0 µg/mL from a representative lot detected the accummulation of ubiquitinated proteins in HEp-2 human epithelial cells following proteasome inhibitor MG-132 (Cat. No. 474790) treatment (Courtesy of Dr. Blagoy Blagoev, University of Southern Denmark).
Other Notes: Concentration: Please refer to lot specific datasheet.