STUDIES ON THE METABOLISM OF <i>p</i>-NITROBENZOIC ACID

Abstract

Para-nitrobenzoic acid may serve as an oxidizable substrate in addition to other metabolic functions in microorganisms. A strain of Pseudomonas fluorescens is capable of using this compound as a sole source of organic carbon and nitrogen for aerobic growth. The enzyme responsible for the oxidation of p-nitrobenzoic acid is adaptive in nature. Experimental results with living, irradiated, and dried-cell preparations indicate that p-aminobenzoic acid, p-hydroxybenzoic acid, and protocatechuic acid are intermediates in the oxidative scheme and the sequence of appearance is in this order. Several other compounds were studied but could not be implicated in the scheme. The nitro group apparently is reduced in vivo to the corresponding amino form. The amino group is then removed as ammonia. By analogy, intermediates in the metabolic scheme of organo nitro compounds might well elucidate the pathway of nitrate reduction.