Ubiquitin-TAMRA-labeled (TMR-Ub)

Post-translational modification of proteins by ubiquitin (Ub) is a key regulatory process that impacts almost all cellular functions. Ubiquitylation occurs through isopeptide linkage between the C-terminus of Ub and the e-amino group of a lysine (Lys) residue on the target substrate [1]. Ub itself has seven Lys residues (6, 11, 27, 29, 33, 48, and 63), any of which can participate in further ubiquitylation, generating polyUb chains [2, 3]. Monitoring the ubiquitylation of target proteins or the growth of polyubiquitin chains has traditionally been carried out with either radiolabeled or epitope-tagged ubiquitin requiring long and laborious detection methods. Fluorescently labeled ubiquitin provides a rapid, facile technique for studying ubiquitin conjugation in vitro. Unlike others, BioVision’s TAMRA-labeled ubiquitin carries a single TAMRA molecule attached at a defined location and avoids modification of either the N-terminus or Lys side chains.