Assists in the loading of diacylglycerol, generated from triacylglycerol stores in the fat body through the action of adipokinetic hormone, into lipophorin, the hemolymph lipoprotein. It increases the lipid carrying capacity of lipophorin by covering the expanding hydrophobic surface resulting from diacylglycerol uptake. It thus plays a critical role in the transport of lipids during flight in several species of insects. Equilibrium between a soluble monomer and a bound lipoprotein form. Apolipophorin-3 associates with lipophorin during lipid loading until each particle contains 14 molecules of apolipophorin-3 in L.migratoria (5 molecules of apolipophorin-3a and 9 of apolipophorin-3b). Hemolymph. Two isoforms of apolipophorin-3 (a and b) have been found and occur in a ratio of 5a:9b in the hemolymph. Belongs to the insect apolipophorin-3 family. Lipid freight - Issue 59 of June 2005