Isolation of a Housefly Head Protein Fraction that Exhibits High Affinity Binding of Cholinergic Ligands

The purification is described of a protein fraction, isolated from the central nervous system of housefly heads, that exhibits high affinity for cholinergic ligands. The purified material was found tq bind with high affinity acetylcholine, nicotinic ligands such as nicotine and decamethonium as well as atropine, dexetimide a:qg pilocarpine which are of a muscarinic nature. With all the ligands there appeared to be only a single site for binding with measured dissociation constants varying from 6.2 X 10-s M (dexetimide) to 5.4 x 10-6 M (pilocarpine). The concentration of binding sites was in the range of 381 nmol g-1 of protein (atropine) to 560 nmol g-1 of protein (pilocarpine)

Isolation of a Housefly Head Protein Fraction that Exhibits High Affinity Binding of Cholinergic Ligands

The purification is described of a protein fraction, isolated from the central nervous system of housefly heads, that exhibits high affinity for cholinergic ligands. The purified material was found tq bind with high affinity acetylcholine, nicotinic ligands such as nicotine and decamethonium as well as atropine, dexetimide a:qg pilocarpine which are of a muscarinic nature. With all the ligands there appeared to be only a single site for binding with measured dissociation constants varying from 6.2 X 10-s M (dexetimide) to 5.4 x 10-6 M (pilocarpine). The concentration of binding sites was in the range of 381 nmol g-1 of protein (atropine) to 560 nmol g-1 of protein (pilocarpine)