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Narrative
Egg white proteins can be selectively precipitated, by adding different concentrations of ammonium sulfate. Ammonium sulfate is highly solvated and reduces the amount of water available for interaction with the protein. A 5% solution of ammonium sulfate is not concentrated enough to precipitate any proteins. When a 20% solution is added, a few proteins precipitate, and a small amount of white solid forms. Increasing the ammonium sulfate concentration decreases the amount of water around the proteins, causing them to precipitate. Adding a 40% ammonium sulfate solution precipitates much more protein. The proteins precipitate, but maintains their tertiary structure.