Mitochondrial membranes reconstituted from lipid-depleted mitochondria and 
aqueous phospholipid dispersions still have the phospholipid negative charges 
available for ionic interaction with the basic protein, lysozyme. The 
stoichiometry of the binding is of about 6 nmoles of lysozyme per 100 nmoles of 
phospholipid in membranes reconstituted with Asolectin, and of 10 nmoles of 
phospholipid phosphorus in membranes reconstituted with cardiolipin. Unextracted 
submitochondrial particles ETP also bind lysozyme (about 3 nmoles per 100 nmoles 
of phospholipid). These observations indicate that the phospholipid anionic 
groups are not completely shielded by the mitochondrial proteins, which might 
occupy areas between the nonpolar groups of the lipid molecules.