[Effect of pepsin on low density serum lipoproteins].

Native lipoproteins of low density from human blood serum were intensively hydrolyzed by pepsin in 0.1 M solution of beta-alanine-HCl at pH 1.9. About 50% and 90% of all the protein part of the substances were split off within 60 min and 22 hrs, respectively. Analytical ultracentrifugation showed that the proteolysis occurred in several steps with formation of discrete intermediates (sedimentation coefficients 2.9 S and 2.3 S at solution density 1,012 g/ml).