[Characteristic of the sites of benz(a)pyrene binding with lysosomal membranes]

Formation of complexes between carcinogenic polycyclic hydrocarbons and lysosomal membranes, exhibiting high inhibitory activity, was studied. Separation of lysosomal membranes into protein and lipid moities and further study of their inhibitory activity enabled to demonstrate that the fraction of lysosomal lipids was responsible for the phenomenon. Elimination of membrane lipids decreased the binding of benz(alpha)pyrene with lysosomes. The carcinogen entering into lysosomal membrane appears to substitute cholesterol in the phospholipid complex, being introduced in the fatty acid chain of phospholipids, thus altering the conformation of protein and protein-lipid complexes in the lysosomal membrane with the subsequent liberation of the lysosomal hydrolytic enzymes into cytoplasm.