A protein (8.5 kD) found in all eukaryotic cells. Can be linked to the lysine side chains of proteins by formation of an amide bond to its C terminal glycine in an ATP requiring process.

The protein/ubiquitin complex is subject to rapid proteolysis. Ubiquitin also has a role in the heat shock response.

This entry appears with permission from the Dictionary of Cell and Molecular Biology

(11 Mar 2008)