The contents of an egg are of two types, the egg yolk (yellow) and the albumin (white). Both of these components are globular proteins in their native form. When egg whites are boiled, they are denatured, resulting into coagulated white protein insoluble in water. In denaturation of protein, the secondary and tertiary structures of egg albumin are converted to primary structure, destroying all the hydrogen bonds that held the structure. The globular protein gets converted into insoluble fibrous protein and the biological activity is lost.