This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Degradation/Utilization/Assimilation → Aromatic Compounds Degradation|
Expected Taxonomic Range: Bacteria
Organophosphate pesticides such as parathion and methyl parathion have been used extensively as insecticides, fungicides, and herbicides. Parathion, which is a cholinesterase inhibitor (see EC 126.96.36.199 and 188.8.131.52 for cholinesterases), is extremely toxic to most animals including humans (in which LD50 is 5 to 10 mg/kg), and may cause death by inducing respiratory failure. The use of Parathion is banned in many countries due to its toxicity and pollutant properties.
About This Pathway
Some bacterial strains are able to degrade parathion and related compounds. A mixed culture of at least 9 isolates was able to grow on parathion as a sole carbon and energy source [Munnecke76, Munnecke76a], although so far no single organism was shown to use parathion as the sole carbon source [Liu05, Sethunathan73].
Two organisms that have been studied in detail are Sphingobium fuliginis [Sethunathan73] and Brevundimonas diminuta [Dumas89]. In both cases parathion degradation starts with the hydrolysis of parathion to 4-nitrophenol and diethylthiophosphate, followed by a second hydrolysis of diethylthiophosphate to diethylphosphate [Munnecke76]. In these organisms, 4-nitrophenol (PNP) was not degraded further, and was released into the environment. The rate of this enzymatic hydrolysis was more than 2000 fold faster than the chemical reaction, as catalyzed by 0.1N sodium hydroxide [Munnecke76a]. This initial hydrolysis of parathion reduces the toxicity by nearly 120-fold [Munnecke79].
The key enzyme in parathion degradation is parathion hydrolase, which has been described in a variety of bacteria. In the bacteria Sphingobium fuliginis and Brevundimonas diminuta the enzyme is encoded by related opd plasmid-borne genes [Mulbry86, McDaniel88, Harper88, Siddavattam03]. Similar enzymes have been purified from additional organisms, and are apparently encoded by genes non-related to the opd genes [Mulbry89]. Parathion hydrolases often have broad substrate range, broad temperature and pH optima, and high stability [Cohen79, Keil89].
Both products of this pathway, 4-nitrophenol and diethylthiophosphate, can be degraded by microorganisms. Two pathways of 4-nitrophenol degradation have been described (see 4-nitrophenol degradation I and 4-nitrophenol degradation II), and the degradation of diethylthiophosphate has been described in several mixed cultures [Shelton88, Ha07]. However, the exact nature of this degradation pathway is not known yet.
It should be mentioned that in the case of the related compound methyl parathion, complete mineralization by a single organism has been reported several times. For more details, see methyl parathion degradation.
This pathway was curated based on a pathway curated in the UM-BBD database [Cornett97].
Relationship Links: Eawag-BBD-Pathways:RELATED-TO:pthn
Harper88: Harper LL, McDaniel CS, Miller CE, Wild JR (1988). "Dissimilar plasmids isolated from Pseudomonas diminuta MG and a Flavobacterium sp. (ATCC 27551) contain identical opd genes." Appl Environ Microbiol 54(10);2586-9. PMID: 3202637
Liu05: Liu H, Zhang JJ, Wang SJ, Zhang XE, Zhou NY (2005). "Plasmid-borne catabolism of methyl parathion and p-nitrophenol in Pseudomonas sp. strain WBC-3." Biochem Biophys Res Commun 334(4);1107-14. PMID: 16039612
Mulbry86: Mulbry WW, Karns JS, Kearney PC, Nelson JO, McDaniel CS, Wild JR (1986). "Identification of a plasmid-borne parathion hydrolase gene from Flavobacterium sp. by southern hybridization with opd from Pseudomonas diminuta." Appl Environ Microbiol 51(5);926-30. PMID: 3015022
Siddavattam03: Siddavattam D, Khajamohiddin S, Manavathi B, Pakala SB, Merrick M (2003). "Transposon-like organization of the plasmid-borne organophosphate degradation (opd) gene cluster found in Flavobacterium sp." Appl Environ Microbiol 69(5);2533-9. PMID: 12732518
Benning94: Benning MM, Kuo JM, Raushel FM, Holden HM (1994). "Three-dimensional structure of phosphotriesterase: an enzyme capable of detoxifying organophosphate nerve agents." Biochemistry 33(50);15001-7. PMID: 7999757
Bondarenko04: Bondarenko S, Gan J, Haver DL, Kabashima JN (2004). "Persistence of selected organophosphate and carbamate insecticides in waters from a coastal watershed." Environ Toxicol Chem 23(11);2649-54. PMID: 15559280
Khajamohiddin06: Khajamohiddin S, Babu PS, Chakka D, Merrick M, Bhaduri A, Sowdhamini R, Siddavattam D (2006). "A novel meta-cleavage product hydrolase from Flavobacterium sp. ATCC27551." Biochem Biophys Res Commun 351(3);675-81. PMID: 17078928
Kitagawa04: Kitagawa W, Kimura N, Kamagata Y (2004). "A novel p-nitrophenol degradation gene cluster from a gram-positive bacterium, Rhodococcus opacus SAO101." J Bacteriol 186(15);4894-902. PMID: 15262926
Perry07: Perry LL, Zylstra GJ (2007). "Cloning of a gene cluster involved in the catabolism of p-nitrophenol by Arthrobacter sp. strain JS443 and characterization of the p-nitrophenol monooxygenase." J Bacteriol 189(21);7563-72. PMID: 17720792
Serdar89: Serdar, C.M., Murdock, D.C., Rohde, M.F. (1989). "Parathion Hydrolase Gene from Pseudomonas diminuta MG: Subcloning, Complete Nucleotide Sequence, and Expression of the Mature Portion of the Enzyme in Escherichia coli." Bio/Technology 7: 1151-1155.
Zhang09: Zhang JJ, Liu H, Xiao Y, Zhang XE, Zhou NY (2009). "Identification and characterization of catabolic para-nitrophenol 4-monooxygenase and para-benzoquinone reductase from Pseudomonas sp. strain WBC-3." J Bacteriol 191(8);2703-10. PMID: 19218392
Zhang12: Zhang S, Sun W, Xu L, Zheng X, Chu X, Tian J, Wu N, Fan Y (2012). "Identification of the para-nitrophenol catabolic pathway, and characterization of three enzymes involved in the hydroquinone pathway, in pseudomonas sp. 1-7." BMC Microbiol 12;27. PMID: 22380602
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