Lipoprotein lipase-catalyzed hydrolysis of dimyristoylphosphatidylcholine. Effect of lipid organization and apolipoprotein C-II on enzyme activity.
The effect of phospholipid organization on the lipoprotein lipase-catalyzed hydrolysis of dimyristoylphosphatidylcholine was examined with sonicated vesicles and Triton X-100 or lysomyristoylphosphatidylcholine solubilized lipid. Triton X-100-dimyristoylphosphatidylcholine substrates were prepared at various ratios of detergent to phospholipid so as to produce lipid structures varying from bilayers to micelles. Apolipoprotein C-II, the activator protein for lipoprotein lipase, enhanced the rate of the lipoprotein lipase-catalyzed hydrolysis of dimyristoylphosphatidylcholine for each substrate tested. Although the absolute rate of lipoprotein lipase catalysis was different for each, the factor (the ratio of lipoprotein lipase activity with apolipoprotein C-II to that without the activator protein) was nearly constant, with a value of approximately 16. We conclude that the enhancement of lipoprotein lipase activity by apolipoprotein C-II is independent of the physical form of the phospholipid substrate.
D000818:Animals; D053304:Apolipoprotein C-II; D053305:Apolipoprotein C-III; D001053:Apolipoproteins / Q000494:pharmacology*; D001056:Apolipoproteins C; D002417:Cattle; D004134:Dimyristoylphosphatidylcholine / Q000378:metabolism*; D004789:Enzyme Activation; D006868:Hydrolysis; D008071:Lipoprotein Lipase / Q000378:metabolism*; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism; D017830:Octoxynol; D011092:Polyethylene Glycols; D012965:Sodium Chloride / Q000494:pharmacology
D053304:Apolipoprotein C-II; D053305:Apolipoprotein C-III; D001053:Apolipoproteins; D001056:Apolipoproteins C; D009227:Myristic Acids; D019814:Myristic Acid; D011092:Polyethylene Glycols; D012965:Sodium Chloride; D017830:Octoxynol; D008071:Lipoprotein Lipase; D004134:Dimyristoylphosphatidylcholine