Effect of 3-Amino-1,2,4-Triazole on Histidine Metabolism in Algae

Abstract
Growth of Chlorella vulgaris and Prototheca zopfii is inhibited by treatment with amino triazole (AT). Growth of these 2 algae in the presence of AT is accompanied by the accumulation in the culture media of the dephosphorylated histidine precursor, imidazole-glycerol (IG). The addition of histidine to the culture media in the presence of AT restored the normal growth rates of these organisms and reduced the accumulation of IG. AT appears to inhibit the synthesis of histidine by interfering with the activity of the enzyme, IG phosphate dehydrase.