Acetylcholine and choline acetyltransferase.

The thermodynamics and kinetics of the alcoholysis of thiolesters are discussed and related to choline acetyltransferase. The conformation and rotational barriers of acetylcholine are described as is the specific inability of choline to induce depolarization. Evidence is presented for the involvement of imidazole and the non-involvement of thiol groups in the active site of choline acetyltransferase. The interaction of CoA and a series of analogs of CoA as well as that of a series of dyes with the CoA binding site is discussed and evidence is presented for the importance of the 3?-phospho group of CoA and an active-site arginine for these interactions.