Abstract: Metallated compounds can be used to extract or precipitate proteins from solution. The compounds can be polymers, such as polyalkylene glycols, which can be mono- or bimetallated or smaller bis-metal chelates, such as ethylenebis(oxyethylenenitrilo)tetraacetic acid. The monometallated polymers are preferred in the extraction process whereas the bimetallated compounds are preferred in the precipitation process. In addition, new PEG compounds which are capable of chelating a variety of metals are described. Both mono- and bi-metallated forms are set forth. The new metallated compounds are very effective in extracting or precipitating proteins from solution.