Metabolites of p-aminobenzoic acid III. A metabolic pathway of p-aminobenzoic acid resulting in the sequential formation of p-aminobenzyl alcohol and p-hydroxyaniline

The following sequence of metabolic reactions has been proved by chemical methods to occur in resting cells of acid-fast bacteria: p-aminobenzoic acid → p-aminobenzyl alcohol → p-hydroxyaniline. The first step in this sequence has been demonstrated to be a direct enzymatic reduction by using both ring- and carboxy-¹⁴C-labeled p-aminobenzoic acid. A synthetic route, which should be of general use, was employed to convert [¹⁴C]aniline to ring-¹⁴C-labeled p-aminobenzoic acid. It is suggested that the unique transformation of p-aminobenzyl alcohol to p-hydroxyaniline may be a specific case of a more general mechanism involved in enzymatic hydroxylation of aryl compounds.