Activation and inactivation kinetics of Torpedo californica acetylcholine receptor in reconstituted membranes

Provided here are quantitative measurements of both activation and inactivation kinetics of AChR-mediated cation flux in reconstituted vesicles containing purified Torpedo californica AChR. Also it is shown that treatment of AChR with the disulfide reducing agent dithiothreitol alters the ligand affinity of the AChR without altering channel properties. These results show that the purified AChR protein retains four important functional characteristics: (1) a high efficiency of cation translocation; (2) a fast inactivation process in the subsecond time domain; (3) a slower inactivation process in the seconds time domain; and (4) a sensitivity to specific chemical modifications. 7 refs., 2 figs