5-enolpyruvylshikimate-3-phosphate synthase (EPSP synthase (or EPSPS))

5-enolpyruvylshikimate-3-phosphate synthase is a monomeric enzyme (~46 kDa) fundamental for the shikimate pathway, which is responsible for the biosynthesis of aromatic amino acids (phenylalanine, tyrosine, tryptophan) in plants, many bacteria, fungi, algae, and certain parasites. EPSPS catalyzes the transfer of the enolpyruvyl group from phosphoenolpyruvate to shikimate 3-phosphate, a crucial and unique step not found in animals. The enzyme is structurally characterized by two domains whose conformational change forms the active site. It is best known as the molecular target of the herbicide glyphosate, which acts as a competitive inhibitor and thereby blocks essential amino acid synthesis, leading to organism death. EPSPS is absent in humans but present in gut flora. In bacteria (e.g., Acinetobacter baumannii), the enzyme is essential for survival and considered a potential antimicrobial target. Recent research has identified isoforms with additional regulatory roles (e.g., transcriptional repression in plant secondary metabolism). Genetically engineered, glyphosate-resistant forms of EPSPS have also been deployed in transgenic crops to confer herbicide resistance[1][2][3][4][5][6][7].

Other names

EPSP synthaseEPSPS5-enolpyruvylshikimate-3-phosphate synthetase3-phosphoshikimate 1-carboxyvinyltransferaseEC 2.5.1.19

Competitive inhibition of the shikimate pathway (herbicides/antibiotics inhibit aromatic amino acid synthesis; glyphosate competitively inhibits PEP binding)