Proteolytic digestion of human serum apolipoproteins by porcine pancreatic elastase.

We studied the proteolytic action in vitro of free and alpha 2-macroglobulin-bound porcine pancreatic elastase [EC 3.4.21.11] on the apolipoproteins of plasma: very low density lipoprotein (VLDL), low density lipoprotein (LDL), and high density lipoprotein (HDL). Polyacrylamide gel electrophoresis, isoelectric focusing and immunodiffusion tests of elastase-treated plasma lipoproteins revealed that apolipoprotein C-II and C-III polypeptides were more susceptible to elastase in free form than plasma apolipoproteins (A-I, A-II, B, and E). Elastase bound to alpha 2-macroglobulin did not show any such activities.