Increasingly, researchers are focusing on the role poly-ubiquitin chains linked through K11. This post-translational modification has been linked to the ERAD cycle as a signal, similar to K48 linkage, for proteasomal degradation. More recently, K11 linkage appears to play an important role in cell cycle signaling, as it is associated with the anaphase promoting complex (APC) of ubiquitination machinery. These tetra-ubiquitin chains are generated from the enzymatic linkage (UBE2S) of wild-type ubiquitin through lysine 11 and purified to >95% homogeneity by ion exchange chromatography. MW: 34.205 kDa (Band migrates faster on gels). Purity ≥95%