E3 ligases

2. E3 ligases assays The E3 ligase family is the largest family in ubiquitin signaling pathway with about 700 members identified or predicted to possess ligase activities. E3 recruits an E2 ubiquitin-conjugating enzyme that has been loaded with ubiquitin, then recognizes a protein substrate, and assists or directly catalyzes the transfer of ubiquitin from the E2 to the protein substrate (Degui, et al. 2016) E3 ubiquitin ligases can be classified into three subfamilies. First is RING E3s, which act as scaffolding molecules to bring ubiquitin-charged E2 enzymes in close contact with their substrates. Second is HECT E3s, which catalyze the transfer of ubiquitin to their own cysteine residues and subsequently to substrates. And the third subfamily, RING-Between-RING (RBR) E3s, which include PARKIN and ARIH1, and mechanistically behave as hybrids between RING and HECT.

4. Basic services offers for E3 ligases . For E3 ligase expression and purification assays, we are providing a broad list of E3 ligases. . For E3 ligase in vitro activity assays, we offer ELISA-based autoubiquitylation or substrate ubiquitylation assay and TR-FRET autoubiquitylation or substrate ubiquitylation assay. . For binding affinities of E3 ligase inhibitors, we offer both thermal shift assay and surface plasmon resonance assay (SPR). . For E3 in cells substrate ubiquitylation assays, we offer ELISA-based substrate ubiquitylation assay and AlphaLISA-based substrate ubiquitylation.