THE SIGNIFICANCE OF THE CARBONYL GROUP AND ETHER OXYGEN IN THE REACTION OF ACETYLCHOLINE WITH RECEPTOR SUBSTANCE

¹ Biological Laboratories, Harvard University, Cambridge, Mass.

In order to determine whether or not the carbonyl group and ether oxygen of acetylcholine are of special significance in the formation of a complex with the acetyicholine receptor protein of the Venus heart a number of analogues have been prepared and tested on this organ. Certain substitutions and changes in position of the carbonyl group result in marked losses in biological activity. It is concluded that a carbonyl group at a maximum distance of 7 Å from a quaternary nitrogen is an important linking group with the receptor protein of the Venus heart. It is suggested that a bond forms between the carbonyl carbon or ketone oxygen and an appropriate group in the protein molecule.