US Patent 7074620 Controlling protein levels in eucaryotic organisms

Method for reducing the level and/or activity of a target protein in a eukaryotic cell via activation of ubiquitination of the target protein wherein the cell is contacted with the compound having a ubiquitination recognition element covalently linked to a target protein binding element. The ubiquitination and recognition element can bind to either the E3 or E2 elements of the ubiquitination system and the target protein binding element is able to bind specifically to the target protein. The target protein binding element has a molecular weight of less than 30,000 and has a binding affinity for the target protein greater than 105M31 1.