title: Cytosolic and nuclear juvenile hormone-binding proteins from the brain of Diploptera punctata.
abstract: Cytosol and crude nuclear extracts of brains from female Diploptera punctata were found to contain a juvenile hormone-binding protein. The binding kinetics of the cytosol and nuclear juvenile hormone-binding proteins toward racemic [3H]JH III were determined using the dextran-coated charcoal assay. Both proteins show reversible and saturable binding toward JH III. The mean dissociation constant (Kd) of the brain cytosol binding protein was 66.5 +/- 7.2 nM, whereas the nuclear-binding protein had a lower affinity, with a mean Kd of 170 +/- 22.1 nM. The specificity of both the cytosol and the nuclear binding proteins was determined by competitive displacement experiments with [3H]JH III. For the cytosol binding protein, the order of relative affinity was JH II > (10R)-JH III > (10RS)-JH III approximately JH I. For the nuclear binding protein the order of relative affinity was JH II > JH I > (10R)-JH III > (10RS)-JH III. The JH analog hydroprene (ZR 512) had > 100-fold lower affinity than JH III for both proteins.
authors.affiliation: Department of Zoology, University of Toronto, ON, Canada.
authors.forename: L E
authors.initials: LE
authors.lastname: King
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: S S
authors.initials: SS
authors.lastname: Tobe
mesh_terms: D000818:Animals; D001667:Binding, Competitive; D001921:Brain / Q000648:ultrastructure*; D002352:Carrier Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000737:chemistry*; D003058:Cockroaches / Q000378:metabolism*; D003600:Cytosol / Q000737:chemistry*; D005260:Female; D019476:Insect Proteins; D007700:Kinetics; D012717:Sesquiterpenes / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D019476:Insect Proteins; D012717:Sesquiterpenes; C035606:juvenile hormone-binding protein, insect; C036585:juvenile hormone III