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Molecular characteristics of lipophorin, the juvenile hormone‐binding protein in the hemolymph of the Colorado potato beetle
Author(s) -
de Kort C. A. D.,
Koopmanschap A. B.
Publication year - 1987
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.940050405
Subject(s) - hemolymph , biology , colorado potato beetle , juvenile hormone , biochemistry , binding protein , hormone , larva , botany , gene
Lipophorin, the protein that specifically binds juvenile hormone in the hemolymph of the Colorado potato beetle, Leptinotarsa decemlineata , is a high‐density lipoprotein of M r ∼ 574,000. Lipophorin contains 43% lipid and is composed of two apoproteins: apolipophorin I (M r ∼ 251,000) and apolipophorin II (M r ∼ 78,000). Both apoproteins contain mannose residues. Carotenoids make up a substantial part of the lipid fraction. Lipophorin constitutes about 25% of the total hemolymph proteins. Its concentration in the hemolymph (26 μM in 4‐day‐old long‐day and 40 μM in 4‐day‐old short‐day beetles) changes with different physiological conditions concomitant with changes in total protein content. Lipophorin specifically binds 10 R ‐juvenile hormone III with high affinity. The dissociation constant for 10 R ‐juvenile hormone III is 12 ± 2 nM. One lipophorin molecule contains one specific juvenile hormone‐binding site. The concentration of binding sites therefore equals that of lipophorin in hemolymph.