Protective Proteins

Pale though it is, the egg white has surprising depths. Of course it supplies the developing embryo with essential water and protein. But biochemical studies have revealed that the albumen proteins are not mere baby food. At least four of the proteins block the action of digestive enzymes. At least three bind tightly to vitamins, which prevents them from being useful to other creatures, and one does the same for iron, an essential mineral for bacteria and animals alike. One protein inhibits the reproduction of viruses, and another digests the cell walls of bacteria. In sum, the egg white is first of all a chemical shield against infection and predation, forged during millions of years of battling between the nourishing egg and a world of hungry microbes and animals.