Triglyceridase and phospholipase A1 activities of rat-heart lipoprotein lipase. Influence of apolipoproteins C-II and C-III.
The influence of purified human apolipoprotein C-II on phospholipase A1 and triglyceridase activities of lipoprotein lipase were compared. Lipoprotein lipase was obtained from rat hearts by perfusion with a medium containing heparin and purified on a heparin Sepharose 4-B column. Using phosphatidyl-ethanolamine-coated triglyceride particles as substrate it was found that the phospholipase A1 and triglyceridase activities of lipoprotein lipase similarly depend on the presence of apolipoprotein C-II. Apolipoprotein C-III cannot replace apolipoprotein C-II. However, addition of apolipoprotein C-III in the presence of C-II affects both lipase activities. While strong inhibition of triglyceridase activity was observed under these conditions, phospholipase A1 activity was slightly stimulated. On the basis of these findings a model was constructed for the role of apolipoprotein C-II in lipoprotein lipase action.
D000818:Animals; D001053:Apolipoproteins / Q000494:pharmacology* / Q000502:physiology; D006801:Humans; D008049:Lipase / Q000302:isolation & purification / Q000378:metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008079:Lipoproteins, VLDL / Q000494:pharmacology / Q000502:physiology; D009206:Myocardium / Q000201:enzymology*; D010740:Phospholipases / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats
D001053:Apolipoproteins; D008079:Lipoproteins, VLDL; D010740:Phospholipases; D008049:Lipase; D008071:Lipoprotein Lipase