A novel lipoprotein from the hemolymph of the cochineal insect, Dactylopius confusus

A new type of insect lipoprotein was isolated from the hemolymph of the fem ale cochineal insect Dactylopius confusus. The lipoprotein from the cochine al insect hemolymph was found to have a relative molecular mass of 450 000. It contains 48% lipid, mostly diacylglycerol, phospholipids and hydrocarbo ns. The protein moiety of the lipoprotein consists of two apoproteins of ap proximately 25 and 22 kDa, both of which are glycosylated. Both apolipoprot eins are also found free in the hemolymph, unassociated with any lipid. Pur ified cochineal apolipoproteins can combine with Manduca sexta lipophorin, if injected together with adipokinetic hormone into M. sexta. This could in dicate that the cochineal lipoprotein can function as a lipid shuttle simil ar to lipophorins of other insects, and that the cochineal insect apolipopr oteins have an overall structure similar to insect apolipophorin-III.