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Biol. Chem. Hoppe-Seyler 367: 1127-1133 (1986)

Proteins and the regulation of lipoprotein lipase activity in locust flight muscle

C H Wheeler , K M Boothby , G J Goldsworthy
ABSTRACT
"Lipoprotein lipases in the flight mucsles of Locusta migratoria show a marked substrate specificity: diacylglycerols associated with the adipokinetic hormone (AKH)-induced lipoprotein, A+, are hydrolysed at 4 to 5 times the rate ot those associated with the lipoprotein in resting (non-hormones-stimulated locusts, Ayellow. (paragraph)To determine the basis for this discrimination, the effect ofn the activity of flight muscle lipoprotein lipase of proteins, a major constituent of lipoprotein A+, but not of Ayellow, has been investigated; they inhibit the flight muscle enayme in a competitive manner whether activity is measured with a natural lipoprotein substrate, a lipid emulsion or a water soluble substrate. (paragraph)Experiments in vivo suggest that the flight muscle enzyme is normally inhibited in resting (non-Astimulated)locusts but, interestingly, injection of synthetic AI relieves the inhibition and increases the activity by 30 to 40%. This is not a direct effect ot the hormone on the enzyme, but appears to be related to the hormone-induced formation of lipoprotein A+, so the the majority of proteins in the haemolymph become bound to this lipoprotein and the concentration of free CL proteins is markedly reduced. We suggest that proteins paly a major role in the regulation of lipoproteinlipase in locust flight muscle."
Notes
Proteins and the regulation of lipoprotein lipase activity in locust flight muscle