Catalyzes the hydrolysis of triglycerides and phospholipids present in circulating plasma lipoproteins, including chylomicrons, intermediate density lipoproteins (IDL), low density lipoproteins (LDL) of large size and high density lipoproteins (HDL), releasing free fatty acids (FFA) and smaller lipoprotein particles. Also exhibits lysophospholipase activity. Can hydrolyze both neutral lipid and phospholipid substrates but shows a greater binding affinity for neutral lipid substrates than phospholipid substrates. In native LDL, preferentially hydrolyzes the phosphatidylcholine species containing polyunsaturated fatty acids at sn-2 position.