Abstract
This paper deals with both the procedure of extraction and the chemical characteristics of the proteinic brain hormone from pupal brains of the silkworm. Acetone dried brains were extracted with phosphate buffer solution and the extract was lyophilized. The 60 μg crude extract yielded positive result on Bombyx-bioassay. The chemical properties of the active extract were examined with heat treatment at 60 or 100°C, buffer treatment at pH 9.9 or 1.4, digestive procedure with some proteolytic enzymes, and fractional precipitation by ammonium sulfate, all results showing that the extract belonged to proteinic substance. Then, the active fraction was separated from the crude extract by means of chromatographic studies with Sephadex and cellulose ion exchanger. When 1 μg of the fraction-V obtained by CM-cellulose column was injected into each of test-objects, the latter became an imago in 3 weeks following the injection. Moreover, the highly purified, active ingredient was separated from the fraction-V on CM-cellulose by means of the zone electrophoresis on acrylamide gel, showing that the ingredient migrated to the anode. Thus two different consituents in the brain extract, sterol and protein showed brain hormone activity.
