Characterization of the proteins from melanoplus bivittatus that bind juvenile hormone, and a refined efda photolabeling technique

1. 1. Juvenile hormone (JH) is specifically bound by a protein from hemolymph and fat body cytosol of the grasshopper, Melanoplus bivittatus. 2. 2. This protein has a native molecular weight of 331,000 and subunits of 77,000. 3. 3. Proteins that bind JH were covalently photolabeled with a JH analog, epoxyfarnesyl diazoacetate (EFDA). Samples were irradiated in spot plates and hydroxyapatite was used to separate bound from free [ 3H]EFDA. Differential solubilization was used to extract unlinked [ 3H]EFDA and solubilize [ 3H]EFDA linked to protein. 4. 4. Hemolymph proteins of M r, 479,000, 240,000 and 77,000 also bound [ 2+H]EFDA. 5. 5. Proteins that bound [ 3,H]EFDA were not vitellogenins.