the effect of phosphorylcholine in promoting the interaction between heparin and pure chylomicrons or very low density lipoproteins was regained when a crude serum protein factor of unwashed chylomicrons was added to the system , suggesting that rat serum contains a protein factor ( s ) which normally inhibits the heparin -- lipoprotein interaction by raising the requirement of ca2+ .
C0008731
chylomicrons
C0023820
lipoprotein