Information AboutUbiquitin |
| CATEGORIES ABOUT UBIQUITIN | |
| proteins | |
| posttranslational modification | |
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The ubiquitylation system was initially characterised as an ATP -dependent proteolytic system present in cellular extracts. A heat-stable Polypeptide present in these extracts, ATP-dependent proteolysis factor 1 (APF-1), was found to become covalently attached to the model protein Substrate Lysozyme in an ATP and Mg 2+-dependent process. Multiple APF-1 molecules were linked to a single Substrate molecule by an isopeptide linkage and conjugates were found to be rapidly degraded with the release of free APF-1. Soon after APF-1-protein conjugation was characterised, APF-1 was identified as ubiquitin. The carboxyl group of the C-terminal glycine residue of ubiquitin (Gly76) was identified as the moiety conjugated to Substrate Lysine residues. THE PROTEIN
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