Hydrolysis of the Lipoprotein Fractions of Milk by Phospholipase C

Phospholipase C hydrolyzed about 90% of the lipid phosphorus of both low-and high-density lipoprotein fractions of milk. Phosphatidyl choline, phosphatidyl ethanolamine and sphingomyelin were most readily hydrolyzed whereas phosphatidyl serine and inositol were only hydrolyzed after the other phospholipids had been almost completely hydrolyzed. By contrast only about 60% of the native phospholipids in milk were hydrolyzed, indicating that some are protected. That phospholipase C inhibited oxidation indicated that the phospholipids available for hydrolysis were also oxidized.