Pathways & interactions
Short name: Phosphotriesterase
Overlapping homologous superfamilies
- Metal-dependent hydrolase (IPR032466)
Bacteria such as Brevundimonas diminuta (Pseudomonas diminuta) harbour a plasmid that carries the gene for phosphotriesterase (PTE also known as parathion hydrolase; EC:220.127.116.11). This enzyme has attracted interest because of its potential use in the detoxification of chemical waste and organophosphate warfare agents such as VX, soman, and sarin, and its ability to degrade agricultural pesticides such as parathion. It acts specifically on synthetic organophosphate triesters and phosphorofluoridates. It does not seem to have a naturally occuring substrate and may thus have optimally evolved for utilising paraoxon.
PTE exists as a homodimer with one active site per monomer. The active site is located next to a binuclear metal centre, at the C-terminal end of a TIM alpha- beta barrel motif. The native enzyme contains two zinc ions at the active site however these can be replaced with other metals such as cobalt, cadmium, nickel or manganese and the enzyme remains active [PMID: 10858282, PMID: 8396425, PMID: 9314115, PMID: 11170459, PMID: 7867909].
PTE belongs to a family [PMID: 9383406, PMID: 9548740] of enzymes that possess a binuclear zinc metal centre at their active site. The two zinc ions are coordinated by six different residues, six of which being histidines. This family so far includes, in addition to the parathion hydrolase, the following proteins:
- Sulfolobus solfataricus aryldialkylphosphatase that has a low paraoxonase activity [PMID: 15909078].
- E. coli php (phosphotriesterase homology) protein. The substrate of php is not yet known [PMID: 9548740].
- Mycobacterium tuberculosis phosphotriesterase homology protein Rv0230C.
- Phospho-furanose lactonase from Mycoplasma [PMID: 24955762].
- Animal phosphotriesterase related protein (PTER) (RPR-1).