IUPAC name
Other names
61-82-5 YesY
3D model (Jmol) Interactive image
Abbreviations 3-AT
ChEBI CHEBI:40036 YesY
ChEMBL ChEMBL232801 YesY
ChemSpider 1577 YesY
ECHA InfoCard 100.000.474
EC Number 200-521-5
KEGG C11261 YesY
RTECS number XZ3850000
Molar mass 84.08
Appearance colorless/white crystals or powder[2]
Density 1.138 g/mol
Melting point 157 to 159 °C (315 to 318 °F; 430 to 432 K)
280 g/liter
Main hazards potential occupational carcinogen
R-phrases R48/22 R51/53 R63
S-phrases (S2) S13 S36/37 S61
Flash point Non-flammable
US health exposure limits (NIOSH):
PEL (Permissible)
REL (Recommended)
Ca TWA 0.2 mg/m3[2]
IDLH (Immediate danger)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

3-Amino-1,2,4-triazole (3-AT) is a heterocyclic organic compound that consists of a 1,2,4-triazole substituted with an amino group.

3-AT is a competitive inhibitor of the product of the HIS3 gene, imidazoleglycerol-phosphate dehydratase.[3][4] Imidazoleglycerol-phosphate dehydratase is an enzyme catalyzing the sixth step of histidine production.[5]

3-AT is also a nonselective systemic triazole herbicide used on nonfood croplands to control annual grasses and broadleaf and aquatic weeds. It is not used on food crops because of its carcinogenic properties. As an herbicide, it is known as aminotriazole, amitrole or amitrol.

Amitrol was included in a biocide ban proposed by the Swedish Chemicals Agency [6] and approved by the European Parliament on January 13, 2009.[7]

Applications in microbiology

By applying 3-AT to a yeast cell culture which is dependent upon a plasmid containing HIS3 to produce histidine (i.e. its own HIS3 analogue is not present or nonfunctional), an increased level of HIS3 expression is required in order for the yeast cell to survive. This has proved useful in various two-hybrid system, where a high-affinity binding between two proteins (i.e., higher expression of the HIS3 gene) will allow the yeast cell to survive in media containing higher concentrations of 3-AT. This selection process is performed using selective media, containing no histidine.

1959 cranberry contamination

On November 9, 1959, the secretary of the United States Department of Health, Education, and Welfare Arthur S. Flemming announced that some of the 1959 crop was tainted with traces of the herbicide aminotriazole. [8] The market for cranberries collapsed and growers lost millions of dollars. [9]


  1. EXTOXNET - Herbicide fact sheet for amitrole
  2. 1 2 3 4 "NIOSH Pocket Guide to Chemical Hazards #0027". National Institute for Occupational Safety and Health (NIOSH).
  3. Brennan MB, Struhl K (1980). "Mechanisms of increasing expression of a yeast gene in Escherichia coli". J. Mol. Biol. 136 (3): 333–8. doi:10.1016/0022-2836(80)90377-0. PMID 6990004.
  4. Joung JK, Ramm EI, Pabo CO (2000). "A bacterial two-hybrid selection system for studying protein-DNA and protein-protein interactions". Proc. Natl. Acad. Sci. U.S.A. 97 (13): 7382–7. doi:10.1073/pnas.110149297. PMC 16554Freely accessible. PMID 10852947.
  5. Yeastgenome.org
  6. "Interpretation of criteria for approval of active substances in the proposed EU plant protection regulation". Swedish Chemicals Agency (KemI). 2008-09-23. Archived from the original on 1 January 2009. Retrieved 2009-01-14.
  7. "MEPs approve pesticides legislation". 2009-01-13. Archived from the original on 25 January 2009. Retrieved 2009-01-14.
  8. "Safe Cranberries to Go on Sale". Dubuqe Telegraph-Herald. 19 November 1959. Retrieved 10 February 2012.
  9. New York Times website - Opinion section
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