If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
|Superclasses:||Biosynthesis → Secondary Metabolites Biosynthesis → Terpenoids Biosynthesis → Hemiterpenes Biosynthesis|
Expected Taxonomic Range: Embryophyta
Isoprene, a gaseous hydrocarbon, is emitted in substantial quantities by many different plant species from mosses to poplar trees [Sharkey08]. Isoprene can affect atmospheric chemistry, and, under particular conditions, can contribute to ozone and aerosol formation in the atmosphere [Sharkey08]. Ozone and aerosols both pose health threats to humans [Sharkey08], and plant growth can also be reduced by elevated ozone levels [Karnosky07].
There are a few potential biological explanations for isoprene emissions by plants. Isoprene appears to help protect plants against sun flecks that can rapidly raise leaf temperatures [Sharkey01, Velikova05]. In addition, isoprene-emitting plants have increased tolerance to ozone and other reactive oxygen species (ROS) [Loreto01, Loreto01a, Affek02, Behnke09]. But, the molecular mechanisms of these isoprene-mediated stress responses are still under investigation. One hypothesis is that isoprene stabilizes lipid membranes [Siwko07].
Levels of isoprene emission are affected by plant developmental stage, circadian rhythms [Wilkinson06, Loivamaki07], and several environmental stimuli (reviewed in [Sharkey08]). Notably, isoprene emissions rise in response to higher temperatures and are light-dependent [Sanadze69, Sharkey08]. The level of isoprene synthase (IspS) activity is correlated with the levels of isoprene emission, indicating that this enzyme is a key regulator of isoprene production. Its activity seems to be largely determined by transcript abundance. Isoprene emissions can also be affected by the level of DMAPP substrate availability, the level of reducing power and ATP, competition with PEP carboxylase for CO2 [Loreto07], and other factors (reviewed in [Sharkey08]).
Isoprene biosynthesis occurs in the chloroplasts and isoprene synthase can be detected in this organelle in a Populus tremula x Populus alba hybrid [Schnitzler05] but extra-chloroplastic sources of DMAPP can also be utilized [Loreto04].
Developing a better understanding of isoprene emissions is necessary for understanding plant development and for predicting atmospheric conditions in the short and long term.
Subpathways: methylerythritol phosphate pathway I
Behnke09: Behnke K, Kleist E, Uerlings R, Wildt J, Rennenberg H, Schnitzler JP (2009). "RNAi-mediated suppression of isoprene biosynthesis in hybrid poplar impacts ozone tolerance." Tree Physiol 29(5);725-36. PMID: 19324699
Karnosky07: Karnosky DF, Skelly JM, Percy KE, Chappelka AH (2007). "Perspectives regarding 50 years of research on effects of tropospheric ozone air pollution on US forests." Environ Pollut 147(3);489-506. PMID: 17084004
Loivamaki07: Loivamaki M, Louis S, Cinege G, Zimmer I, Fischbach RJ, Schnitzler JP (2007). "Circadian rhythms of isoprene biosynthesis in grey poplar leaves." Plant Physiol 143(1);540-51. PMID: 17122071
Loreto01: Loreto F, Velikova V (2001). "Isoprene produced by leaves protects the photosynthetic apparatus against ozone damage, quenches ozone products, and reduces lipid peroxidation of cellular membranes." Plant Physiol 127(4);1781-7. PMID: 11743121
Loreto01a: Loreto F, Mannozzi M, Maris C, Nascetti P, Ferranti F, Pasqualini S (2001). "Ozone quenching properties of isoprene and its antioxidant role in leaves." Plant Physiol 126(3);993-1000. PMID: 11457950
Loreto04: Loreto F, Pinelli P, Brancaleoni E, Ciccioli P (2004). "13C labeling reveals chloroplastic and extrachloroplastic pools of dimethylallyl pyrophosphate and their contribution to isoprene formation." Plant Physiol 135(4);1903-7. PMID: 15286296
Loreto07: Loreto, F., Centritto, M., Barta, C., Calfapietra, C., Fares, S., Monson, R.K. (2007). "The relationship between isoprene emission rate and dark respiration rate in white poplar (Populus alba L.) leaves." Plant, Cell, and Environment. 30(5): 662-669.
Miller01: Miller B, Oschinski C, Zimmer W (2001). "First isolation of an isoprene synthase gene from poplar and successful expression of the gene in Escherichia coli." Planta 213(3);483-7. PMID: 11506373
Schnitzler05: Schnitzler JP, Zimmer I, Bachl A, Arend M, Fromm J, Fischbach RJ (2005). "Biochemical properties of isoprene synthase in poplar (Populus x canescens)." Planta 222(5);777-86. PMID: 16052321
Schwender97: Schwender J, Zeidler J, Groner R, Muller C, Focke M, Braun S, Lichtenthaler FW, Lichtenthaler HK (1997). "Incorporation of 1-deoxy-D-xylulose into isoprene and phytol by higher plants and algae." FEBS Lett 414(1);129-34. PMID: 9305746
Siwko07: Siwko ME, Marrink SJ, de Vries AH, Kozubek A, Schoot Uiterkamp AJ, Mark AE (2007). "Does isoprene protect plant membranes from thermal shock? A molecular dynamics study." Biochim Biophys Acta 1768(2);198-206. PMID: 17125733
Velikova05: Velikova, V., Loreto, F. (2005). "On the relationship between isoprene emission and thermotolerance in Phragmites australis leaves exposed to high temperatures and during the recovery from a heat stress." Plant, Cell, and Environment. 28 (3): 318-327.
Wilkinson06: Wilkinson MJ, Owen SM, Possell M, Hartwell J, Gould P, Hall A, Vickers C, Nicholas Hewitt C (2006). "Circadian control of isoprene emissions from oil palm (Elaeis guineensis)." Plant J 47(6);960-8. PMID: 16899082
Adam02: Adam P, Hecht S, Eisenreich W, Kaiser J, Grawert T, Arigoni D, Bacher A, Rohdich F (2002). "Biosynthesis of terpenes: studies on 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase." Proc Natl Acad Sci U S A 99(19);12108-13. PMID: 12198182
Altincicek01: Altincicek B, Kollas AK, Sanderbrand S, Wiesner J, Hintz M, Beck E, Jomaa H (2001). "GcpE is involved in the 2-C-methyl-D-erythritol 4-phosphate pathway of isoprenoid biosynthesis in Escherichia coli." J Bacteriol 183(8);2411-6. PMID: 11274098
Anderson89: Anderson MS, Muehlbacher M, Street IP, Proffitt J, Poulter CD (1989). "Isopentenyl diphosphate:dimethylallyl diphosphate isomerase. An improved purification of the enzyme and isolation of the gene from Saccharomyces cerevisiae." J Biol Chem 1989;264(32);19169-75. PMID: 2681212
Bernal05: Bernal C, Palacin C, Boronat A, Imperial S (2005). "A colorimetric assay for the determination of 4-diphosphocytidyl-2-C-methyl-D-erythritol 4-phosphate synthase activity." Anal Biochem 337(1);55-61. PMID: 15649375
Cane01: Cane DE, Chow C, Lillo A, Kang I (2001). "Molecular cloning, expression and characterization of the first three genes in the mevalonate-independent isoprenoid pathway in Streptomyces coelicolor." Bioorg Med Chem 9(6);1467-77. PMID: 11408165
CarreteroPaulet02: Carretero-Paulet L, Ahumada I, Cunillera N, Rodriguez-Concepcion M, Ferrer A, Boronat A, Campos N (2002). "Expression and molecular analysis of the Arabidopsis DXR gene encoding 1-deoxy-D-xylulose 5-phosphate reductoisomerase, the first committed enzyme of the 2-C-methyl-D-erythritol 4-phosphate pathway." Plant Physiol 129(4);1581-91. PMID: 12177470
deRuyck06: de Ruyck J, Durisotti V, Oudjama Y, Wouters J (2006). "Structural role for Tyr-104 in Escherichia coli isopentenyl-diphosphate isomerase: site-directed mutagenesis, enzymology, and protein crystallography." J Biol Chem 281(26);17864-9. PMID: 16617181
Dogbo87: Dogbo, O., Camara, B. (1987). "Purification of isopentenyl pyrophosphate isomerase and geranylgeranyl pyrophosphate synthase from Capsicum chromoplasts by affinity chromatography." Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism 920(2):140-148.
Durbecq01: Durbecq V, Sainz G, Oudjama Y, Clantin B, Bompard-Gilles C, Tricot C, Caillet J, Stalon V, Droogmans L, Villeret V (2001). "Crystal structure of isopentenyl diphosphate:dimethylallyl diphosphate isomerase." EMBO J 20(7);1530-7. PMID: 11285217
Estevez00: Estevez JM, Cantero A, Romero C, Kawaide H, Jimenez LF, Kuzuyama T, Seto H, Kamiya Y, Leon P (2000). "Analysis of the expression of CLA1, a gene that encodes the 1-deoxyxylulose 5-phosphate synthase of the 2-C-methyl-D-erythritol-4-phosphate pathway in Arabidopsis." Plant Physiol 124(1);95-104. PMID: 10982425
Estevez01: Estevez JM, Cantero A, Reindl A, Reichler S, Leon P (2001). "1-Deoxy-D-xylulose-5-phosphate synthase, a limiting enzyme for plastidic isoprenoid biosynthesis in plants." J Biol Chem 276(25);22901-9. PMID: 11264287
Feurle02: Feurle J, Espinosa E, Eckstein S, Pont F, Kunzmann V, Fournie JJ, Herderich M, Wilhelm M (2002). "Escherichia coli produces phosphoantigens activating human gamma delta T cells." J Biol Chem 277(1);148-54. PMID: 11675382
Fox05: Fox DT, Poulter CD (2005). "Synthesis and evaluation of 1-deoxy-D-xylulose 5-phosphoric acid analogues as alternate substrates for methylerythritol phosphate synthase." J Org Chem 70(6);1978-85. PMID: 15760175
Showing only 20 references. To show more, press the button "Show all references".
©2015 SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025-3493