title: Isolation and characterization of apolipophorin-III from the giant water bug (Lethocerus medius).
abstract: Upon injection of synthetic adipokinetic hormone, lipophorin from Lethocerus medius decreased in density and became associated with apolipophorin-III (apoLp-III). ApoLp-III isolated from hemolymph of Lethocerus medius had a M(r) = 19,000 and an amino acid composition high in methionine, in comparison with other apoLp-IIIs. Its circular dichroism spectrum was consistent with a protein with secondary structure of predominantly alpha-helix. NH2-terminal sequence alignment with apoLp-III sequences from other species showed a conservation of the hydrophobic or hydrophilic properties of residues at each position rather than of specific amino acids. ApoLp-III from Lethocerus medius has the potential to form amphipathic alpha-helices, similar to those found in the three-dimensional structure of Locusta migratoria apoLp-III. A portion of the apoLp-III molecules that are not associated with lipophorin contained the blue chromophore, biliverdin.
authors.affiliation: Department of Biochemistry, University of Arizona, Tucson 85721, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Kanost
authors.forename: K A
authors.initials: KA
authors.lastname: Sparks
authors.forename: M A
authors.initials: MA
authors.lastname: Wells
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001053:Apolipoproteins / Q000097:blood*; D001664:Biliverdine / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D006430:Hemiptera / Q000737:chemistry*; D006458:Hemolymph / Q000737:chemistry / Q000187:drug effects; D007301:Insect Hormones / Q000494:pharmacology; D008074:Lipoproteins; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D017386:Sequence Homology, Amino Acid
chemical_list: D001053:Apolipoproteins; D002352:Carrier Proteins; D007301:Insect Hormones; D008074:Lipoproteins; D009842:Oligopeptides; C044833:adipokinetic hormone; C042470:apolipophorin III; C032830:lipophorin; D001664:Biliverdine; D011761:Pyrrolidonecarboxylic Acid