K48-Tetra-Ubiquitin Fluorescein-Labeled - 25 µg

Poly-ubiquitylation of target proteins through linkage at K48 is the most thoroughly studied of the various ubiquitin chain linkages. It is now clear that many, if not all, poly-Ub chain topologies are likely to play distinct and important roles in regulating cellular processes. Nevertheless, K48 linkages remain a critical pathway for cells to maintain protein homeostasis and remain intriguing for the study of DUBs that play a role in regulating degradation, as well as the proteasome itself. These tetra-ubiquitin chains are generated by the enzymatic linkage of wild-type ubiquitin through lysine 48. The most distal ubiquitin contains a Lys48 to Arg substitution limiting chain length.  The fluorescein moiety is attached to a single, non-lysine site in the proximal ubiquitin.