Egg white is the common name for the clear liquid (also called the albumen or the glair/glaire) contained within an egg. It is the cytoplasm of the egg, which until fertilization is a single cell (including the yolk). It consists mainly of about 15% proteins dissolved in water. Its primary natural purpose is to protect the egg yolk and provide additional nutrition for the growth of the embryo, as it is rich in proteins and also of high nutritional value. Unlike the egg yolk, it contains a negligible amount of fat. Egg whites have many culinary and non-culinary uses for humans. Lysozymes, also known as muramidase or N-acetylmuramide glycanhydrolase, are a family of enzymes (EC 188.8.131.52) which damage bacterial cell walls by catalyzing hydrolysis of 1,4-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in a peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrins. Lysozyme is abundant in a number of secretions, such as tears, saliva, and mucus. It is also present in cytoplasmic granules of the polymorphonuclear neutrophils (PMN). Large amounts of lysozyme can be found in egg white. C-type lysozymes are closely related to alpha-lactalbumin in sequence and structure making them part of the same family. In humans, the lysozyme enzyme is encoded by the LYZ gene.