A. De Vries

Action of snake-venom phospholipase a on free and lipoprotein-bound phospholipids

Abstract Snake-venom phospholipase A was found to split phospholipids present in egg yolk and human serum at a ten- to twenty-fold higher rate than purified ovolecithin preparations. On the other hand, with total lipid extracts derived from egg yolk or serum the enzyme activity was as low as with isolated lecithin. The experimental evidence favors the conclusion that the higher substrate efficiency of the crude phospholipids in their native state, unaltered by the isolation procedures is attributable to the specific nature of their combination with proteins in the form of lipoprotein complexes. The mechanism underlying the characteristic changes induced by phospholipase A in the electrophoretic pattern of the serum proteins, is discussed in relation alteration caused by lipoprotein lipase. The significance of the lipoprotein structure is considered in the light of the available information concerning the action of snake-venom phospholipase in vivo and in vitro.