Juvenile-hormone-binding protein from the hemolymph of Galleria mellonella (L). Isolation and characterization.
A juvenile-hormone-binding protein (JHBP) has been isolated from Galleria mellonella hemolymph by gel filtration, phosphocellulose chromatography, and by chromatofocusing. The isolated protein is homogeneous as judged by column chromatography and gel electrophoresis in the presence and absence of denaturing agent. It has a relative molecular mass of 32,000, Stokes radius 2.4 nm, sedimentation coefficient of 2.3 S, molar absorption coefficient at 280 nm epsilon = 2.34 X 10(4) M-1 cm-1, and is composed of a single polypeptide chain. Chromatofocusing analysis (pI 8.6) and isoelectric focusing (pI 8.1) indicate that the JHBP is an alkaline protein. Its amino acid composition and fluorescence absorption spectra indicate that the protein does not contain tryptophan residues. The protein exhibits one class of binding sites for juvenile hormone (JH), 0.8 per molecule, with the following dissociation constants: JH I, 8.5 X 10(-8) M; JH II, 7.2 X 10(-8) M; JH III, 47 X 10(-8) M. The JHBP binds (10R, 11S)-JH II enantiomer with 2.3-times higher affinity then (10S, 11R)-JH II enantiomer. The pH optimum of binding is 7.0.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002352:Carrier Proteins / Q000302:isolation & purification*; D002499:Centrifugation, Density Gradient; D002845:Chromatography / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel; D006458:Hemolymph / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D019476:Insect Proteins; D007525:Isoelectric Focusing; D007915:Lepidoptera; D008970:Molecular Weight; D013050:Spectrometry, Fluorescence
D000596:Amino Acids; D002352:Carrier Proteins; D019476:Insect Proteins; C035606:juvenile hormone-binding protein, insect