title: Evidence for presence of an arginine residue in the coenzyme A binding site of choline acetyltransferase.
abstract: Choline acetyltransferase (acetyl-CoA:choline O-acetyltransferase, EC 2.3.1.6) may be inactivated by arginine-specific reagents such as butanedione, phenylglyoxal, and camphorquinone-10-sulfonic acid. The enantiomers of the latter compound were prepared, but inactivation was not stereospecific. Protection against inactivation by the arginine-specific reagents was provided by CoA and, to a lesser extent, by 3'-dephospho-CoA. No protection was provided by choline, NAD+, NADH, NADP+, or NADPH. Sodium chloride could protect, to some extent, against inactivation by arginine-specific reagents; this protection showed no cation or anion specificity. The data are compatible with the postulate that the salt anion competes with the attachment of the 3'-phospho group of CoA to an active site arginine residue.
mesh_terms: D000105:Acetyl Coenzyme A / Q000378:metabolism*; D000818:Animals; D001120:Arginine; D001665:Binding Sites; D002164:Camphor / Q000031:analogs & derivatives / Q000494:pharmacology; D002795:Choline O-Acetyltransferase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D049832:Decapodiformes; D003931:Diacetyl / Q000494:pharmacology; D010658:Phenylglyoxal / Q000494:pharmacology; D013237:Stereoisomerism
chemical_list: D000105:Acetyl Coenzyme A; C023633:camphorquinone-10-sulfonic acid; D002164:Camphor; D001120:Arginine; D002795:Choline O-Acetyltransferase; D003931:Diacetyl; D010658:Phenylglyoxal