title: Apolipophorin III in locusts: purification and characterization.
abstract: Three molecular species of apolipophorin III were purified from adult locust hemolymph by gel filtration and ion-exchange chromatography, and named apo-III-a, apo-III-b, and apo-III-c, respectively. They were indistinguishable by SDS-polyacrylamide gel electrophoresis, immunodiffusion, and in amino acid composition; however, they had different isoelectric points (5.43 for a, 5.11 for b, and 4.98 for c) and, therefore, could be separated by native- or urea-gel electrophoresis. All three apo-IIIs were glycoproteins and contained fucose, mannose, and glucosamine. The total sugar content amounted to about 11% for each of the three apo-IIIs. The molecular weight of apo-III determined by SDS-polyacrylamide gel electrophoresis was approximately 20,000, almost equivalent to the native molecular weight (approximately 19,000) estimated by the sedimentation-equilibrium method. This indicated that the locust apo-III exists in hemolymph as a monomeric form. It was demonstrated that a total 9 moles of apo-III (2 moles apo-III-a, 6 moles apo-III-b, and 1 mole apo-III-c) associate with each mole of lipophorin in response to the action of locust adipokinetic hormone.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001053:Apolipoproteins / Q000145:classification / Q000302:isolation & purification*; D002241:Carbohydrates / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D006110:Grasshoppers; D007124:Immunoenzyme Techniques; D007526:Isoelectric Point; D008970:Molecular Weight; D011487:Protein Conformation
chemical_list: D000596:Amino Acids; D001053:Apolipoproteins; D002241:Carbohydrates; C042470:apolipophorin III