Proteins are not lost during cooking as easily as vitamins; however overcooking and cooking at extremely high temperatures will denature proteins found in food. When cooked or agitated (as occurs when egg whites are beaten), proteins undergo physical changes called denaturation and coagulation. Denaturation changes the shape of the protein, decreasing the solubility of the protein molecule. Coagulation causes protein molecules to clump together, as occurs when making scrambled eggs. Overcooking foods containing protein can destroy heat-sensitive amino acids (for example, lysine) or make the protein more resistant to digestive enzymes. Refrigerating cooked foods will not further denature the proteins.