Main Entry: ubiq·ui·tin Pronunciation: yü-'bik-w&t-&n Function: noun : a chiefly eukaryotic protein that when covalently bound toother cellular proteins marks them for proteolytic degradation
ubiquitin u·biq·ui·tin (y&oomacr;-bĭk'wĭ-tĭn) n. A polypeptide found in all eukaryotic cells including plant cells that participates in a variety of cellular functions including protein degradation.