COENZYME FOR ACETYLATION, A PANTOTHENIC ACID DERIVATIVE

The action of a novel coenzyme of general occurrence was first observed with acetylation of aromatic amines in liver preparations.'The analogous acetylation system for choline in brain was subsequently found to require the same coenzyme,2 undoubtedly ident.icalwith the activator for choline acetylation concurrently described by Feldberg and Mann,3 Nachmansohn and Berman,4 and Lipton.6Recently, by a variation of the steps described earlier,6 we obtained a preparation of this coenzyme which was 700 times as active as the original boiled pork liver extracts.This preparation was subjected to a thorough vitamin analysis.None of the known I3 vitamins were found in more than traces.It was observed, however, that by prolongation of the routine treatment with clarase-papain before the assay7 the pantothenic acid values increased slowly.Therefore @-alanine* was determined in the acid hydrolysate and values were obtained corresponding t,o a content in the coenzyme of 10 per cent pantothenic acid.Eventually pantothenic acid was liberated by a combination of t,wo enzymes previously found6 to inactivate the coenzyme (Table I).To characterize the coenzyme further as a pantothenic acid derivative, the pantothenic acid content and coenzyme activity mere compared in a series of preparations (Table II).The constancy of vitamin content per unit gives further evidence that pantothenic acid is part. of the coenzyme.