ACTION OF A HISTIDINE ANALOGUE, 1,2,4-TRIAZOLE-3-ALANINE, IN SALMONELLA TYPHIMURIUM

Levin, Alfred P. (The Johns Hopkins University, Baltimore, Md.),and Philip E. Hartman . Action of a histidine analogue, 1,2,4-triazole-3-alanine, inSalmonella typhimurium . J. Bacteriol.86: 820–828. 1963.—The effect of the histidine analogue, 1,2,4-triazole-3-alanine (TRA), on growth and enzyme synthesis in histidine auxotrophs ofSalmonella typhimurium has been studied. TRA allows an increase of approximately 50% in the amount of protein in a culture but does not allow concomitant synthesis of ribonucleic acid and deoxyribonucleic acid. Although the analogue prevents the formation of active bacteriophage and of enzymatically active inosine 5′-phosphate dehydrogenase, it does not prevent the formation of enzymatically activel -histidinol phosphate phosphatase or of imidazoleacetol phosphate transaminase, two enzymes involved in the biosynthesis of histidine. Of the three known functions of histidine in the cell, TRA mimics two: it is incorporated into protein, and it acts as a repressor material for synthesis of enzymes involved in the formation of histidine. TRA fails to act as a feedback inhibitor of the first step in the formation of histidine.