Search

Salt solutions and charged detergents are efficient solubilizing agents for ovovitelline membrane lysozyme. Reassociation experiments with chemically modified lysozymes indicate that positively charged amino acid residues of lysozyme (the epsilon-amino group of lysine and the guanidino group of arginine) are involved in the interaction with other proteins of the vitelline membrane. Exogenous proteins are adsorbed to lysozyme-free vitelline membranes, only if they have a high pI, comparable to that of lysozyme. It is concluded that the lysozyme-ovovitelline membrane interaction is predominantly ionic. An ovomucin-lysozyme complex is postulated as the major component of the outer layer of the membrane.

Lysozyme accounts for 37% of the proteins of the hen's egg vitelline membrane. It can be extracted by salt solutions and purified by gel filtration on Sephadex G-50. There are no differences between the chemical and enzymic properties of egg white and vitelline membrane lysozymes. Vitelline membranes of ovarian eggs do not contain lysozyme. It is thus concluded that lysozyme is localized in the outer layer. Vitelline membranes from fertilized and unfertilized eggs contain the same amount of lysozyme; its percentage decreases after two days of incubation.