Some factors affecting the acetylation of p-aminobenzoic acid in the rat.

The acetylation reaction involving detoxification of various aromatic amines both in vitro and in viva has become of new importance with the discovery by Lipmann et al. (1) that the coenzyme necessary for this coupling contains pantothenic acid. In an earlier paper (2), we gave evidence demonstrating that pantothenic acid is necessary for normal acetylation of p-aminobenzoic acid (PAB) by rats. Although many studies have been made on the general reaction (3), the lack of agreement on results suggests that the conditions under which the measurements are made may be predominant in determining the results. It appears desirable, therefore, to reexamine some of the factors which previous work has suggested might affect the extent of the over-all coupling reaction when PAB is administered to rats. Studies reported here consist of three parts: (1) an examination of the effect of thiamine and riboflavin deficiencies on acetylation to see whether low acetylation is specific for pantothenic acid deficiency; (2) a measure of the effect of added acetate on the acetylation by deficient animals in order to eliminate low acetate supply as a possible cause of low acetylation; and (3) a measure of the effect of the amount of PAB administered on the degree of acetylation.