Abstract
p-Aminobenzoic acid (PABA) exerts three metabolic effects on E. coli: it acts as a normal vitamin at low concentrations, as a source of another vitamin, p-hydroxybenzoic acid (POB), at moderate concentrations, and as a growth inhibitor at high concentrations (150 to 1600 µg./ml.). The inhibition is competitively reversed by POB in 1/100 the concentration of PABA. The inhibition is also reversed to a limited extent by shikimic acid and compound X, precursors of POB. p-Nitrobenzoic acid is an inhibitory competitor of both POB and PABA. The retardation of growth produced by PABA and other competitive analogues of POB (p-nitrobenzoic acid; 4,4'-dihydroxydiphenyl sulfone; phenosulfazole) is converted to complete bacteriostasis by the addition of L-aspartic acid in a remarkably low concentration (1 µg./ml.)) without change in the competitive ratio with POB. The mechanism underlying this synergism is not clear. In contrast to wild type, mutants that require POB not only are inhibited by much lower concentrations of the above analogues, but also show inhibition by weaker competitors of POB such as p-hydroxybenzenesulfonamide, p-chlorobenzoic acid, and p-fluorobenzoic acid.
Full Text
The Full Text of this article is available as a PDF (564.2 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- DAVIS B. D. Aromatic biosynthesis. I. The role of shikimic acid. J Biol Chem. 1951 Jul;191(1):315–325. [PubMed] [Google Scholar]
- DAVIS B. D., MINGIOLI E. S. Mutants of Escherichia coli requiring methionine or vitamin B12. J Bacteriol. 1950 Jul;60(1):17–28. doi: 10.1128/jb.60.1.17-28.1950. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DAVIS B. D. p-Hydroxybenzoic acid; a new bacterial vitamin. Nature. 1950 Dec 30;166(4235):1120–1121. doi: 10.1038/1661120b0. [DOI] [PubMed] [Google Scholar]
- Greiff D., Pinkerton H., Moragues V. EFFECT OF ENZYME INHIBITORS AND ACTIVATORS ON THE MULTIPLICATION OF TYPHUS RICKETTSIAE : I. PENICILLIN, PARA-AMINOBENZOIC ACID, SODIUM FLUORIDE, AND VITAMINS OF THE B GROUP. J Exp Med. 1944 Dec 1;80(6):561–574. doi: 10.1084/jem.80.6.561. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MAAS W. K., DAVIS B. D. Pantothenate studies. I. Interference by D-serine and L-aspartic acid with pantothenate synthesis in Escherichia coli. J Bacteriol. 1950 Dec;60(6):733–745. doi: 10.1128/jb.60.6.733-745.1950. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ZALOKAR M. The sulfonamide-requiring mutant of Neurospora: threonine-methionine antagonism. J Bacteriol. 1950 Aug;60(2):191–203. doi: 10.1128/jb.60.2.191-203.1950. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Zalokar M. The p-Aminobenzoic Acid Requirement of the "Sulfonamide-Requiring" Mutant Strain of Neurospora. Proc Natl Acad Sci U S A. 1948 Feb;34(2):32–36. doi: 10.1073/pnas.34.2.32. [DOI] [PMC free article] [PubMed] [Google Scholar]