Ubiquitin (Ub) is a 76 amino acid protein widely expressed in the cytoplasmic and nucleus of cells. Ub is posttranslationally conjugated to proteins by the E1, E2, E3 protein ubiquitination cascade. Ub can be conjugated on proteins as monoUb or polyUb chains. Protein ubiquitination plays both proteolytic and nonproteolytic functions. Usually, polyubiquitinated proteins are targeted to the 26S proteasome for proteolysis. Typical concentration to support in vitro ubiquitination is 50-100 µM. In Ub(K48 only), all lysine residues but lysine 48 were substituted with arginines, thereby it only supports the formation of lysine 48-linked polyubiquitin chains.

Ubiquitin (Ub) is a 76 amino acid protein widely expressed in the cytoplasmic and nucleus of cells. Ub is posttranslationally conjugated to proteins by the E1, E2, E3 protein ubiquitination cascade. Ub can be conjugated on proteins as monoUb or polyUb chains. Protein ubiquitination plays both proteolytic and nonproteolytic functions. Usually, polyubiquitinated proteins are targeted to the 26S proteasome for proteolysis. Typical concentration to support in vitro ubiquitination is 50-100 µM. In Ub(K48 only), all lysine residues but lysine 48 were substituted with arginines, thereby it only supports the formation of lysine 48-linked polyubiquitin chains.
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Coomassie-stained SDS-PAGE
Lane 1: Molecular weight markers
Lane 2: 5 µg purified 6xHis-Ubiquitin (K0)
Lane 3: 5 µg purified 6xHis-Ubiquitin (K6 only)
Lane 4: 5 µg purified 6xHis-Ubiquitin (K11 only)
Lane 5: 5 µg purified 6xHis-Ubiquitin (K27 only)
Lane 6: 5 µg purified 6xHis-Ubiquitin (K29 only)
Lane 7: 5 µg purified 6xHis-Ubiquitin (K33 only)
Lane 8: 5 µg purified 6xHis-Ubiquitin (K48 only)
Lane 9: 5 µg purified 6xHis-Ubiquitin (K63 only)