Effect of structurally related compounds on the oxidation of p-aminobenzoic acid by Pseudomonas fluorescens.

The realization that p-aminobenzoic acid is essential as a growth factor has stimulated extensive research in the field of antagonists of this essential metabolite. Woods (1940) and Woods and Fildes (1940) reported that yeast contained a substance, identified as p-aminobenzoic acid, that could protect it against the growth inhibiting action of sulfanilamide. Youmans et al. (1947) reported the tuberculostatic action of p-aminosalicylic acid for virulent strains of the human type tubercle bacilli, and their results indicated that this action was, at least in part, due to anti-p-aminobenzoic acid activity. Davis (1951) and Davis and Maas (1952) reported that both p-aminobenzoic acid and p-hydroxybenzoic acid were essential for growth of certain strains of Escherichia coli, and that p-nitrobenzoic acid competitively interfered with the utilization of these metabolites. In addition to functioning as a growth factor, p-aminobenzoic acid may also serve as an oxidizable substrate for certain microorganisms (Durham, 1956). This paper is concerned with the effect of known antimetabolites and other structurally related compounds on the oxidative metabolism of p-aminobenzoic acid by Pseudomonas fluorescens.