PROSITE documentation PDOC01026
Phosphotriesterase family signature and profile


Bacteria such as Pseudomonas diminuta harbor a plasmid that carries the gene for the enzyme phosphotriesterase (EC (PTE) (also known as parathion hydrolase). This enzyme has attracted interest because of its potential use in the detoxification of chemical waste and warfare agents and its ability to degrade agricultural pesticides such as parathion. It act specifically on synthetic organophosphate triesters and phosphorofluoridates. It does not seem to have a natural occuring substrate and may thus have optimally evolved for utilizing paraoxon.

PTE belongs to a family [1,2] of enzymes that possess a binuclear zinc metal center at their active site. This family so far includes, in addition to the parathion hydrolase, the following proteins:

  • Escherichia coli protein php. The substrate of php is not yet known.
  • Mycobacterium tuberculosis phosphotriesterase homology protein Rv0230C.
  • Mammalian phosphotriesterase related protein (PTER) (RPR-1).

The two zinc ions are coordinated by six different residues, four of which being histidines. We have developed a signature pattern for this family of enzymes, which corresponds to a region located in the N-terminal section. That contains two histidines that bind the first of the two zinc ions. We also developed a profile that covers the entire phosphotriesterase and has been manually adapted to detect each of the six zinc-binding residues.

Last update:

December 2007 / Pattern removed, profile added and text revised.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

PHOSPHOTRIESTERASE_2, PS51347; Phosphotriesterase family profile  (MATRIX)

PHOSPHOTRIESTERASE_1, PS01322; Phosphotriesterase family signature 1  (PATTERN)


1AuthorsScanlan T.S. Reid R.C.
TitleEvolution in action.
SourceChem. Biol. 2:71-75(1995).
PubMed ID9383406

2AuthorsBuchbinder J.L. Stephenson R.C. Dresser M.J. Pitera J.W. Scanlan T.S. Fletterick R.J.
TitleBiochemical characterization and crystallographic structure of an Escherichia coli protein from the phosphotriesterase gene family.
SourceBiochemistry 37:5096-5106(1998).
PubMed ID9548740

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