Mechanism of RING E3-mediated Catalysis

The prediction of the effective concentration model has been tested in an in vitro system reconstituted with El, E2 (UbcHS), and all purified to 90% 

Although the ubiquitination site(s) of -catenin was previously unknown, two lysines of I/cBa located ten and nine residues upstream of the destruction motif had been shown to be necessary and sufficient for ubiquitination and degradation [18, 19]. By analogy, a jS-catenin lysine (Lysl9) 13 residues upstream of the destruction motif was predicted to be the site where / -catenin is ubiquitinated. This was confirmed by the in vitro ubiquitination assay, in which a 26-amino acid j8-catenin peptide that contains Lysl9 and the doubly phosphorylated destruction motif was ubiquitinated in an -dependent manner to an overall level comparable to an 

---