Abstract
C18:juvenile hormone is quite soluble in water, yielding a monomeric solution greater than 10-5 M. In vivo injection or addition of aqueous juvenile hormone to the hemolymph in vitro shows the complexation of juvenile hormone to a protein, as demonstrated by gel permeation chromatography and disc-gel electrophoresis. The protein has an apparent molecular weight of 3.4 × 104 and is present in the hemolymph at a concentration in the micromolar range. The binding of the hormone to the protein can be described as a simple thermodynamic equilibrium with a dissociation constant of 3 × 10-7 M, and the protein has a much higher affinity for the hormone than for the hydrolysis products.
Keywords: tobacco hornworm, dissociation constant, specificity, esterases, diisopropylphosphofluoridate
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Selected References
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