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.
Synonyms: detoxification of small reactive electrophile species in chloroplasts
Some taxa known to possess this pathway include : Arabidopsis thaliana col
Expected Taxonomic Range: Embryophyta
Oxidative stress in plants often occurs in response to biotic and abiotic stresses. The reactive oxygen species that form under oxidative stress can damage numerous biomolecules, including proteins and lipids. The chloroplast, an organelle often subject to oxidative stress, contains a high proportion of linolenic and linoleic acids in its membrane. When these prevalent fatty acids undergo lipid peroxidation, a variety of short-chain carbonyls may be formed. A subset of these, α,β-unsaturated carbonyls, such as acrolein are known to cause damage to cells and tissues. In chloroplasts, this damage can threaten to disrupt to vital process of photosynthesis [Yamauchi, Mano09, Almeras03]. Therefore, several mechnisms for detoxifying these reactive carbonyl compounds are present in chloroplasts [Yamauchi11]. Glutathione-S-transferase (GST)-based modification of toxic compounds is one robust system that is supported by high levels of glutathione in the chloroplast. But, there is evidence that compounds such as acrolein reduce the rate of photosynthesis when glutathione needed for detoxification in not available to allow the function of several Calvin cycle enzymes [Mano09]. The NADPH-dependent set of reactions depicted in this metabolic cluster provide another means for reducing the toxicity of reactive eletrophilic carbonyl compounds in the chloroplast [Yamauchi11, Simpson09].
Similar pathways for detoxification are likely to exist in the mitochondria and cytosol, but, they will be carried out by a set of related enzymes present in those compartments [Yamauchi11].
About This Pathway
Two different type of enzymatic activities that can be used to minimize the threat posed by reactive carbonyl compounds are shown in this metabolic cluster.
AOR acts to reduce the the unsaturated bond on α,β-unsaturated carbonyls, leading to the production of saturated ketones and aldehydes. Although the action of this enzyme is important, it cannot detoxify the whole assortment of reactive carbonyl compounds on its own. First, it does not show strong activity against α,β-unsaturated carbonyls that have more than 5 carbons. Second, the saturated aldehydes produced by AOR can also be dangerous to the plant. Therefore, additional enzymes with over-lapping substrate specificities, namely, a chloroplastic aldo-keto reductase and chloroplastic aldehyde reductase contribute to the protection of this organelle by reducing the carbonyl groups on toxic compounds to yield the corresponding alcohols [Yamauchi11, Simpson09].
Variants: 4-hydroxy-2-nonenal detoxification , ascorbate glutathione cycle , baicalein degradation (hydrogen peroxide detoxification) , cyanate degradation , farnesylcysteine salvage pathway , fluoroacetate degradation , furfural degradation , glutathione-mediated detoxification I , glutathione-mediated detoxification II , methanol oxidation to carbon dioxide , mycothiol-mediated detoxification , oxidized GTP and dGTP detoxification , seleno-amino acid detoxification and volatilization III , superpathway of seleno-compound metabolism
Almeras03: Almeras E, Stolz S, Vollenweider S, Reymond P, Mene-Saffrane L, Farmer EE (2003). "Reactive electrophile species activate defense gene expression in Arabidopsis." Plant J 34(2);205-16. PMID: 12694595
Simpson09: Simpson PJ, Tantitadapitak C, Reed AM, Mather OC, Bunce CM, White SA, Ride JP (2009). "Characterization of two novel aldo-keto reductases from Arabidopsis: expression patterns, broad substrate specificity, and an open active-site structure suggest a role in toxicant metabolism following stress." J Mol Biol 392(2);465-80. PMID: 19616008
Yamauchi: Yamauchi Y, Furutera A, Seki K, Toyoda Y, Tanaka K, Sugimoto Y "Malondialdehyde generated from peroxidized linolenic acid causes protein modification in heat-stressed plants." Plant Physiol Biochem 46(8-9);786-93. PMID: 18538576
Yamauchi11: Yamauchi Y, Hasegawa A, Taninaka A, Mizutani M, Sugimoto Y (2011). "NADPH-dependent Reductases Involved in the Detoxification of Reactive Carbonyls in Plants." J Biol Chem 286(9);6999-7009. PMID: 21169366
Bondoc99: Bondoc FY, Bao Z, Hu WY, Gonzalez FJ, Wang Y, Yang CS, Hong JY (1999). "Acetone catabolism by cytochrome P450 2E1: studies with CYP2E1-null mice." Biochem Pharmacol 58(3);461-3. PMID: 10424765
Bruce08: Bruce TJ, Matthes MC, Chamberlain K, Woodcock CM, Mohib A, Webster B, Smart LE, Birkett MA, Pickett JA, Napier JA (2008). "cis-Jasmone induces Arabidopsis genes that affect the chemical ecology of multitrophic interactions with aphids and their parasitoids." Proc Natl Acad Sci U S A 105(12);4553-8. PMID: 18356298
Choi08: Choi HW, Lee BG, Kim NH, Park Y, Lim CW, Song HK, Hwang BK (2008). "A role for a menthone reductase in resistance against microbial pathogens in plants." Plant Physiol 148(1);383-401. PMID: 18599651
Grant03a: Grant AW, Steel G, Waugh H, Ellis EM (2003). "A novel aldo-keto reductase from Escherichia coli can increase resistance to methylglyoxal toxicity." FEMS Microbiol Lett 218(1);93-9. PMID: 12583903
Mano05: Mano J, Belles-Boix E, Babiychuk E, Inze D, Torii Y, Hiraoka E, Takimoto K, Slooten L, Asada K, Kushnir S (2005). "Protection against photooxidative injury of tobacco leaves by 2-alkenal reductase. Detoxication of lipid peroxide-derived reactive carbonyls." Plant Physiol 139(4);1773-83. PMID: 16299173
Miller09: Miller EN, Jarboe LR, Yomano LP, York SW, Shanmugam KT, Ingram LO (2009). "Silencing of NADPH-dependent oxidoreductase genes (yqhD and dkgA) in furfural-resistant ethanologenic Escherichia coli." Appl Environ Microbiol 75(13);4315-23. PMID: 19429550
Rutschow08: Rutschow H, Ytterberg AJ, Friso G, Nilsson R, van Wijk KJ (2008). "Quantitative proteomics of a chloroplast SRP54 sorting mutant and its genetic interactions with CLPC1 in Arabidopsis." Plant Physiol 148(1);156-75. PMID: 18633119
Salas06: Salas JJ, Garcia-Gonzalez DL, Aparicio R (2006). "Volatile compound biosynthesis by green leaves from an Arabidopsis thaliana hydroperoxide lyase knockout mutant." J Agric Food Chem 54(21);8199-205. PMID: 17032029
Tooker02: Tooker JF, Koenig WA, Hanks LM (2002). "Altered host plant volatiles are proxies for sex pheromones in the gall wasp Antistrophus rufus." Proc Natl Acad Sci U S A 99(24);15486-91. PMID: 12438683
Van01a: Van Poecke RM, Posthumus MA, Dicke M (2001). "Herbivore-induced volatile production by Arabidopsis thaliana leads to attraction of the parasitoid Cotesia rubecula: chemical, behavioral, and gene-expression analysis." J Chem Ecol 27(10);1911-28. PMID: 11710601
Vander92: Vander Jagt DL, Robinson B, Taylor KK, Hunsaker LA (1992). "Reduction of trioses by NADPH-dependent aldo-keto reductases. Aldose reductase, methylglyoxal, and diabetic complications." J Biol Chem 267(7);4364-9. PMID: 1537826
Vukovic09: Vukovic N, Sukdolak S, Solujic S, Niciforovic N (2009). "Antimicrobial activity of the essential oil obtained from roots and chemical composition of the volatile constituents from the roots, stems, and leaves of Ballota nigra from Serbia." J Med Food 12(2);435-41. PMID: 19459749
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