Treatment of low density lipophorin with lipoprotein lipase: diacylglycerol content has no effect on dissociation of apolipophorin III from low-density lipophorin.
The mechanism of the conversion of low-density lipophorin (LDLp) to high-density lipophorin (HDLp) in long-distance flight insects was investigated using a lipoprotein lipase from a bacterium, Alcaligenes sp. Diacylglycerol of LDLp was steadily hydrolyzed in vitro by the lipase, resulting in a 90% loss of diacylglycerol from LDLp during incubation. The "lipase-treated LDLp" thus obtained still contained associated apolipophorin-III (apoLp-III). These data suggest that the dissociation of apoLp-III is independent of the depletion of diacylglycerol from LDLp, and that the decrease in particle diameter caused by the depletion of diacylglycerol does not force the dissociation of apoLp-III from the lipophorin particle. Some physico-chemical properties of the lipase-treated LDLp were measured.
Hiraoka
T
T
Biochemistry Laboratory, Hokkaido University.
Katagiri
C
C
D000421:Alcaligenes / Q000201:enzymology; D000818:Animals; D001053:Apolipoproteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism* / Q000648:ultrastructure; D002942:Circular Dichroism; D004075:Diglycerides / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006110:Grasshoppers; D006868:Hydrolysis; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008074:Lipoproteins; D008297:Male; D008854:Microscopy, Electron
D001053:Apolipoproteins; D002352:Carrier Proteins; D004075:Diglycerides; D008074:Lipoproteins; C042470:apolipophorin III; C032830:lipophorin; D008071:Lipoprotein Lipase