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Mano J, Miyatake F, Hiraoka E, Tamoi M. Evaluation of the toxicity of stress-related aldehydes to photosynthesis in chloroplasts. PLANTA 2009; 230:639-48. [PMID: 19578873 DOI: 10.1007/s00425-009-0964-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Accepted: 05/18/2009] [Indexed: 05/03/2023]
Abstract
Aldehydes produced under various environmental stresses can cause cellular injury in plants, but their toxicology in photosynthesis has been scarcely investigated. We here evaluated their effects on photosynthetic reactions in chloroplasts isolated from Spinacia oleracea L. leaves. Aldehydes that are known to stem from lipid peroxides inactivated the CO(2) photoreduction to various extents, while their corresponding alcohols and carboxylic acids did not affect photosynthesis. alpha,beta-Unsaturated aldehydes (2-alkenals) showed greater inactivation than the saturated aliphatic aldehydes. The oxygenated short aldehydes malondialdehyde, methylglyoxal, glycolaldehyde and glyceraldehyde showed only weak toxicity to photosynthesis. Among tested 2-alkenals, 2-propenal (acrolein) was the most toxic, and then followed 4-hydroxy-(E)-2-nonenal and (E)-2-hexenal. While the CO(2)-photoreduction was inactivated, envelope intactness and photosynthetic electron transport activity (H(2)O --> ferredoxin) were only slightly affected. In the acrolein-treated chloroplasts, the Calvin cycle enzymes phosphoribulokinase, glyceraldehyde-3-phosphate dehydrogenase, fructose-1,6-bisphophatase, sedoheptulose-1,7-bisphosphatase, aldolase, and Rubisco were irreversibly inactivated. Acrolein treatment caused a rapid drop of the glutathione pool, prior to the inactivation of photosynthesis. GSH exogenously added to chloroplasts suppressed the acrolein-induced inactivation of photosynthesis, but ascorbic acid did not show such a protective effect. Thus, lipid peroxide-derived 2-alkenals can inhibit photosynthesis by depleting GSH in chloroplasts and then inactivating multiple enzymes in the Calvin cycle.
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Affiliation(s)
- Jun'ichi Mano
- Science Research Center, Yamaguchi University, Yamaguchi 753-8515, Japan.
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2
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Serrato AJ, Yubero-Serrano EM, Sandalio LM, Muñoz-Blanco J, Chueca A, Caballero JL, Sahrawy M. cpFBPaseII, a novel redox-independent chloroplastic isoform of fructose-1,6-bisphosphatase. PLANT, CELL & ENVIRONMENT 2009; 32:811-27. [PMID: 19220782 DOI: 10.1111/j.1365-3040.2009.01960.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A full-length FBPase cDNA has been isolated from Fragaria x ananassa (strawberry) corresponding to a novel putative chloroplastic FBPase but lacking the regulatory redox domain, a characteristic of the plastidial isoenzyme (cpFBPaseI). Another outstanding feature of this novel isoform, called cpFBPaseII, is the absence of the canonical active site. Enzymatic assays with cpFBPaseII evidenced clear Mg(2+)-dependent FBPase activity and a K(m) for fructose-1,6-bisphosphate (FBP) of 1.3 mM. Immunolocalization experiments and chloroplast isolation confirmed that the new isoenzyme is located in the stroma. Nevertheless, unlike cpFBPaseI, which is redox activated, cpFBPaseII did not increase its activity in the presence of either DTT or thioredoxin f (TRX f) and is resistant to H(2)O(2) inactivation. Additionally, the novel isoform was able to complement the growth deficiency of the yeast FBP1 deletion fed with a non-fermentable carbon source. Furthermore, orthologues are restricted to land plants, suggesting that cpFBPaseII is a novel and an intriguing chloroplastic FBPase that emerged late in the evolution of photosynthetic organisms, possibly because of a pressing need of land plants.
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Tejwani GA. Regulation of fructose-bisphosphatase activity. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 54:121-94. [PMID: 6303063 DOI: 10.1002/9780470122990.ch3] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Chueca A, Sahrawy M, Pagano EA, López Gorgé J. Chloroplast fructose-1,6-bisphosphatase: structure and function. PHOTOSYNTHESIS RESEARCH 2002; 74:235-49. [PMID: 16245135 DOI: 10.1023/a:1021243110495] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Redox regulation of photosynthetic enzymes has been a preferred research topic in recent years. In this area chloroplast fructose-1,6-bisphosphatase is probably the most extensively studied target enzyme of the CO(2) assimilation pathway. This review analyzes the structure, biosynthesis, phylogeny, action mechanism, regulation and kinetics of fructose-1,6-bisphosphatase in the light of recent findings on structure-function relationship, and from a molecular biology viewpoint.
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Affiliation(s)
- Ana Chueca
- Department of Biochemistry, Cell and Molecular Biology of Plants, Estación Experimental del Zaidín (CSIC), Prof. Albareda 1, 18008, Granada, Spain,
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Minot R, Meunier JC, Buc J, Ricard J. The role of pH and magnesium concentration in the light activation of chloroplastic fructose bisphosphatase. FEBS Lett 2001. [DOI: 10.1016/0014-5793(82)80232-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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6
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Rosa L. The rapid activation in vitro of the chloroplast fructose 1,6-bisphosphatase followed using a new assay procedure. FEBS Lett 2001. [DOI: 10.1016/0014-5793(81)80589-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ashton AR. A simple procedure for purifying the major chloroplast fructose-1,6-bisphosphatase from spinach (Spinacia oleracea) and characterization of its stimulation by sub-femtomolar mercuric ions. Arch Biochem Biophys 1998; 357:207-24. [PMID: 9735161 DOI: 10.1006/abbi.1998.0818] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A rapid procedure for the purification of the redox-regulated chloroplast fructose-1,6-bisphosphatase [EC 3.1.3.11] from spinach leaf extract to homogeneity is described. No thiol-reducing agents were present during the purification and the enzyme is > 99% in the oxidized form. A rapid procedure to reduce and activate the Fru-1,6-P2ase by dithiothreitol in the absence of thioredoxin is described. Reduction activates the enzyme up to several hundred-fold when assayed at pH 8.0 with 2 mM Mg2+. The activity of the purified oxidized enzyme is unusually sensitive to changes in Mg2+ and H+ concentration. Tenfold changes in Mg2+ or H+ concentration lead to > 100-fold increases in activity. The recoveries of fructose-1,6-bisphosphatase activity as determined by the activity of the oxidized enzyme at pH 8.0/20 mM Mg2+; pH 9.0/2 mM Mg2+; pH 8/2 mM Mg2+ plus 0.1 mM Hg(II) or of the reduced enzyme at pH 8.0/2 mM Mg2+ are similar (approximately 40%) indicating that the major proportion of these activities in a leaf extract is catalyzed by the same enzyme. Moreover, antibodies raised against the purified enzyme inhibit all of the above activities in crude leaf extracts. The kinetic properties of the purified enzyme suggest that the oxidized Mg(2+)-dependent enzyme can play no significant role in photosynthetic carbon assimilation. A survey of some kinetic properties of Fru-1,6-P2ase activity in extracts of various photosynthetic organisms reveals that all 11 species examined possess a redox- and pH/Mg(2+)-stimulated Fru-1,6-P2ase, whereas Fru-1,6-P2ase in extracts of Taxus baccata (a gymnosperm), Chlorella vulgaris (a green alga), and the cyanobacterium Nostoc muscorum were not activated by Hg(II). The heat stability that proved useful in the purification of the spinach enzyme was conserved in both angiosperms and gymnosperms. The oxidized enzyme (which normally has no thiol groups accessible to 5,5'-dithio-bis[2-nitrobenzoic acid]) but not the reduced enzyme can be stimulated many hundred-fold by addition of extraordinarily low concentrations of Hg(II) to a complete assay mixture. With the aid of EDTA as a Hg(II) buffer, half-maximal stimulation was achieved at 2 x 10(-16) M free Hg(II). Methylmercury also stimulates the enzyme many hundred-fold at very low concentrations. The concentration for half-maximal stimulation by methylmercury was determined with a cyanide buffer to be approximately 10(-16) M. This, together with the high affinity of the enzyme for Hg(II), suggests that Hg(II) stimulates the enzyme by binding to an enzyme thiol group that be comes exposed in the catalytically active enzyme, thereby stabilizing the oxidized enzyme in an active conformation. By contrast, in the absence of Fru-1,6-P2 and either Mg2+ or Ca2+, Hg(II) (even at 2 x 10(-16) M) rapidly inactivates the oxidized Fru-1,6-P2ase. This inactivation is similar to the inactivation of Fru-1,6-P2ase that occurred at high pH (> 9) and which is also prevented by Fru-1,6-P2 and either Mg2+ or Ca2+. Although the Hg(II)- and high pH-inactivated oxidized enzyme has no activity, both forms of the enzyme can be activated by reduction. The usefulness of buffers to maintain low, defined Hg(II) and organic mercurial concentrations is discussed.
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Affiliation(s)
- A R Ashton
- Lehrstuhl fur Pflanzenphysiologie, Universität Bayreuth, Germany.
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9
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Chen Y, Wu JW, Xu GJ, Tsou CL, Wang ZX. Inactivation kinetics of the reduced spinach chloroplast fructose-1,6-bisphosphatase by subtilisin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 248:925-9. [PMID: 9342248 DOI: 10.1111/j.1432-1033.1997.00925.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The course of inactivation of the reduced spinach chloroplast fructose-1,6-bisphosphatase by digestion with subtilisin has been followed by the progress curve method [Tsou, C. L. (1988) Adv. Enzymol. 61, 381-436] and found to follow first-order kinetics. On the basis of the hydrolysis of the substrate, fructose 1,6-bisphosphate, at different concentrations during proteolysis by subtilisin, the first-order inactivation rate constants for the free enzyme and the enzyme-substrate complex can both be determined. The ratio between the inactivation rate constants for the free enzyme and the enzyme-substrate complex indicates strong protection against subtilisin proteolysis by the substrate. It is proposed that the above ratio can be used as a quantitative measure of substrate protection for enzyme inactivation generally. As it has been found that the site of proteolysis is located in a loop region near the N-terminus and well away from the active site, the substrate protection indicates a conformation change of the enzyme away from the substrate binding site.
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Affiliation(s)
- Y Chen
- National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Bejiing, China
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Nel W, Terblanche SE. Plant fructose-1,6-bisphosphatases: characteristics and properties. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1992; 24:1267-83. [PMID: 1322844 DOI: 10.1016/0020-711x(92)90201-b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In this minireview the properties and characteristics of plant fructose-1,6-bisphosphatases (D-fructose-1,6-bisphosphatase 1-phosphohydrolase, EC 3.1.3.11) are discussed. The properties and characteristics of the chloroplastic and cytoplasmic forms of the enzyme are reviewed. For purposes of comparison some reference is made to fructose-1,6-bisphosphatases from other species.
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Affiliation(s)
- W Nel
- Department of Biochemistry, University of Zululand, Private Bag, Republic of South Africa
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11
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Botha FC, Turpin DH. Fructose 1,6-Bisphosphatase in the Green Alga Selenastrum minutum: I. Evidence for the Presence of Isoenzymes. PLANT PHYSIOLOGY 1990; 93:1460-5. [PMID: 16667640 PMCID: PMC1062695 DOI: 10.1104/pp.93.4.1460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Two isoforms of fructose 1,6-bisphosphatase are present in the green alga Selenastrum minutum. The isoenzymes can be separated with ionexchange chromatography or acid precipitation. The stability of the two isoenzymes differ largely. The acid insoluble enzyme exhibits properties similar to that of the enzyme from the chloroplasts of higher plants, i.e. an alkaline pH optima in the absence of reductant, a lower affinity for substrate, strong inhibition by phosphate, and a low sensitivity to fructose-2,6-bisphosphate and AMP. The more abundant form of the enzyme exhibits several properties indicative of heterotrophic fructose 1,6 bisphosphatases, i.e. a high affinity for substrate and sensitivity toward fructose-2,6-bisphosphate and AMP. but is absolutely dependent on a reductant for stability and activity. Evidence is provided indicating that previously reported purification protocols cause inactivation of one of the isoenzymes which could lead to the erroneous conclusion that algae have a single fructose 1,6-bisphosphatase isoenzyme.
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Affiliation(s)
- F C Botha
- Department of Botany, University of the Orange Free State, Bloemfontein 9300, South Africa
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13
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Stein M, Lazaro JJ, Wolosiuk RA. Concerted action of cosolvents, chaotropic anions and thioredoxin on chloroplast fructose-1,6-bisphosphatase. Reactivity to iodoacetamide. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 185:425-31. [PMID: 2555190 DOI: 10.1111/j.1432-1033.1989.tb15132.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The incubation of chloroplast fructose-1,6-bisphosphatase with both dithiothreitol and protein denaturants made sulfhydryl groups available for reaction with [1-14C]iodoacetamide (10-12 mol iodoacetamide incorporated/mol enzyme). Digestion of S-carboxyamidomethylated enzyme with trypsin and polyacrylamide gel electrophoresis, in the presence of sodium dodecylsulfate, yielded two 14C-labeled fragments whose apparent molecular mass were 10 kDa and 16 kDa. In the absence of either dithiothreitol or protein denaturants the incorporation of iodoacetamide to the enzyme was lower than 4 mol. When chloroplast fructose-1,6-bisphosphatase was initially incubated with dithiothreitol (2.5 mM) and (a) high concentrations of both fructose 1,6-bisphosphate (4 mM) and Ca2+ (0.3 mM) or (b) low concentrations of both fructose 1,6-bisphosphate (0.8 mM) and Ca2+ (0.05 mM) in the presence of either 2-propanol (15%, by vol.), trichloroacetate (0.15 M) or chloroplast thioredoxin-f (0.5 microM) and subsequently subjected to proteolysis and electrophoresis, S-carboxyamidomethylated tryptic fragments had similar molecular masses. Thus, conditions that stimulated the specific activity of chloroplast fructose-1,6-bisphosphatase caused conformational changes which favoured both the reduction of disulfide bridges and the exposure of sulfhydryl groups. In this aspect, thioredoxin exerted structural and kinetic effects similar to compounds not involved in redox reactions (organic solvents, chaotropic anions). These results indicated that the modification of hydrophobic (intramolecular) interactions in chloroplast fructose-1,6-bisphosphatase constituted the underlying mechanism in light-activation by the ferredoxin-thioredoxin system.
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Affiliation(s)
- M Stein
- Instituto de Investigaciones Bioquímicas, Fundación Campomar, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
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14
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Leegood RC, Labate CA, Huber SC, Neuhaus HE, Stitt M. Phosphate sequestration by glycerol and its effects on photosynthetic carbon assimilation by leaves. PLANTA 1988; 176:117-126. [PMID: 24220742 DOI: 10.1007/bf00392487] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/1988] [Accepted: 05/19/1988] [Indexed: 06/02/2023]
Abstract
Glycerol induced a limitation on photosynthetic carbon assimilation by phosphate when supplied to leaves of barley (Hordeum vulgare L.) and spinach (Spinacia oleracea L.). This limitation by phosphate was evidenced by (i) reversibility of the inhibition of photosynthesis by glycerol by feeding orthophosphate (ii) a decrease in light-saturated rates of photosynthesis and saturation at a lower irradiance, (iii) the promotion of oscillations in photosynthetic CO2 assimilation and in chlorophyll fluorescence, (iv) decreases in the pools of hexose monophosphates and triose phosphates and increases in the ratio of glycerate-3-phosphate to triose phosphate, (v) decreased photochemical quenching of chlorophyll fluorescence, and increased non-photochemical quenching, specifically of the component which relaxed rapidly, indicating that thylakoid energisation had increased. In barley there was a massive accumulation of glycerol-3-phosphate and an increase in the period of the oscillations, but in spinach the accumulation of glycerol-3-phosphate was comparatively slight. The mechanism(s) by which glycerol feeding affects photosynthetic carbon assimilation are discussed in the light of these results.
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Affiliation(s)
- R C Leegood
- Research Institute for Photosynthesis and Department of Plant Sciences, University of Sheffield, S10 2TN, Sheffield, UK
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Pettersson G, Ryde-Pettersson U. A mathematical model of the Calvin photosynthesis cycle. EUROPEAN JOURNAL OF BIOCHEMISTRY 1988; 175:661-72. [PMID: 3137030 DOI: 10.1111/j.1432-1033.1988.tb14242.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
1. A mathematical model is presented for photosynthetic carbohydrate formation in C3 plants under conditions of light and carbon dioxide saturation. The model considers reactions of the Calvin cycle with triose phosphate export and starch production as main output processes, and treats concentrations of NADPH, NAD+, CO2, and H+ as fixed parameters of the system. Using equilibrium approximations for all reaction steps close to equilibrium steady-state and transient-state relationships are derived which may be used for calculation of reaction fluxes and concentrations of the 13 carbohydrate cycle intermediates, glucose 6-phosphate, glucose 1-phosphate, ATP, ADP, and inorganic (ortho)phosphate. 2. Predictions of the model were examined with the assumption that photosynthate export from the chloroplast occurs to a medium containing orthophosphate as the only exchangeable metabolite. The results indicate that the Calvin cycle may operate in a single dynamically stable steady state when the external concentration of orthophosphate does not exceed 1.9 mM. At higher concentrations of the external metabolite, the reaction system exhibits overload breakdown; the excessive rate of photosynthate export deprives the system of cycle intermediates such that the cycle activity progressively approaches zero. 3. Reactant concentrations calculated for the stable steady state that may obtain are in satisfactory agreement with those observed experimentally, and the model accounts with surprising accuracy for experimentally observed effects of external orthophosphate on the steady-state cycle activity and rate of starch production. 4. Control analyses are reported which show that most of the non-equilibrium enzymes in the system have a strong regulatory influence on the steady-state level of all of the cycle intermediates. Substrate concentration control coefficients for cycle enzymes may be positive, such that an increase in activity of an enzyme may raise the steady-state concentration of the substrate is consumes. 5. Under optimal external conditions (0.15-0.5 mM orthophosphate), reaction flux in the Calvin cycle is controlled mainly by ATP synthetase and sedoheptulose bisphosphatase; the cycle activity approaches the maximum velocity that can be supported by the latter enzyme. At lower concentrations of external orthophosphate the cycle activity is controlled almost exclusively by the phosphate translocator.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- G Pettersson
- Avdelningen för Biokemi, Lunds Universitet, Sweden
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Noctor G, Mills JD. Thiol modulation of the thylakoid ATPase. Lack of oxidation of the enzyme in the presence of ΔμH+ in vivo and a possible explanation of the physiological requirement for thiol regulation of the enzyme. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1988. [DOI: 10.1016/0005-2728(88)90107-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pettersson G, Ryde-Pettersson U. A rapid-equilibrium model for the control of the Calvin photosynthesis cycle by cytosolic orthophosphate. EUROPEAN JOURNAL OF BIOCHEMISTRY 1987; 169:423-9. [PMID: 3691500 DOI: 10.1111/j.1432-1033.1987.tb13629.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
1. A simple model based on rapid-equilibrium assumptions is derived which relates the steady-state activity of the Calvin cycle for photosynthetic carbohydrate formation in C3 plants to the kinetic properties of a single cycle enzyme (fructose bisphosphatase) and of the phosphate translocator which accounts for the export of photosynthate from the chloroplast. Depending on the kinetic interplay of these two catalysts, the model system may exhibit a single or two distinct modes of steady-state operation, or may be unable to reach a steady state. 2. The predictions of the model are analysed with regard to the effect of external orthophosphate on the steady-state rate of photosynthesis in isolated chloroplasts under conditions of saturating light and CO2. Due to the possible existence of two distinct steady states, the model may account for the stimulatory as well as the inhibitory effects of external phosphate observed in experiments with intact chloroplasts. Stability arguments indicate, however, that only the steady-state case corresponding to phosphate inhibition of the rate of photosynthesis could be of physiological interest. 3. It is concluded that chloroplasts under physiological conditions most likely operate in a high-velocity steady state characterized by a negative Calvin cycle flux control coefficient for the phosphate translocator. This means that any factor enhancing the export capacity of the phosphate translocator can be anticipated to decrease the actual steady-state rate of photosynthate export due to a decreased steady-state rate of cyclic photosynthate production.
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Affiliation(s)
- G Pettersson
- Avdelningen för Biokemi, Kemicentrum, Lunds Universitet, Sweden
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18
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Noctor G, Mills JD. Control of CO2 fixation during the induction period. The role of thiol-mediated enzyme activation in the alga, Dunaliella. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1987. [DOI: 10.1016/0005-2728(87)90199-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Clancey CJ, Gilbert HF. Thiol/disulfide exchange in the thioredoxin-catalyzed reductive activation of spinach chloroplast fructose-1,6-bisphosphatase. Kinetics and thermodynamics. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(19)76462-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Brown D, Kershaw KA. Isolation and Characterization of Two Enzymes Capable of Hydrolyzing Fructose-1,6-Bisphosphatase from the Lichen Peltigera rufescens. PLANT PHYSIOLOGY 1986; 82:462-7. [PMID: 16665052 PMCID: PMC1056141 DOI: 10.1104/pp.82.2.462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Two enzymes capable of hydrolyzing fructose-1,6-bisphosphate (FBP) have been isolated from the foliose lichen Peltigera rufescens (Weis) Mudd. These enzymes can be separated using Sephadex G-100 and DEAE Sephacel chromatography. One enzyme has a pH optimum of 6.5, and a substrate affinity of 228 micromolar FBP. This enzyme does not require MgCl(2) for activity, and is inhibited by AMP. The second enzyme has a pH optimum of 9.0, with no activity below pH 7.5. This enzyme responds sigmoidally to Mg(2+), with half-saturation concentration of 2.0 millimolar MgCl(2), and demonstrates hyperbolic kinetics for FBP (K(m) = 39 micromolar). This enzyme is activated by 20 millimolar dithiothreitol, is inhibited by AMP, but is not affected by fructose-2-6-bisphosphate. It is hypothesized that the latter enzyme is involved in the photosynthetic process, while the former enzyme is a nonspecific acid phosphatase.
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Affiliation(s)
- D Brown
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 4K1
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21
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Control of the rate of photosynthetic carbon dioxide fixation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1986. [DOI: 10.1016/0005-2728(86)90124-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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Gardemann A, Schimkat D, Heldt HW. Control of CO2 fixation regulation of stromal fructose-1,6-bisphosphatase in spinach by pH and Mg(2+) concentration. PLANTA 1986; 168:536-45. [PMID: 24232331 DOI: 10.1007/bf00392274] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/1985] [Accepted: 01/30/1986] [Indexed: 05/06/2023]
Abstract
The effect of pH and of Mg(2+) concentration on the light activated form of stromal fructose-1,6-bisphosphatase (FBPase) was studied using the enzyme rapidly extracted from illuminated spinach chloroplasts. The (fructose-1,6-bisphosphate(4-))(Mg(2+)) complex has been identified as the substrate of the enzyme. Therefore, changes of pH and Mg(2+) concentrations have an immediate effect on the activity of FBPase by shifting the pH and Mg(2+) dependent equilibrium concentration of the substrate. In addition, changes of pH and Mg(2+) concentration in the assay medium have a delayed effect on FBPase activity. A correlation of the activities observed using different pH and Mg(2+) concentrations indicates, that the effect is not a consequence of the pH and Mg(2+) concentration as such, but is caused by a shift in the equilibrium concentration of a hypothetical inhibitor fructose-1,6-bisphosphate(3-) (uncomplexed), resulting in a change of the activation state of the enzyme. The interplay between a rapid effect on the concentration of the substrate and a delayed effect on the activation state enables a rigid control of stromal FBPase by stromal Mg(2+) concentrations and pH. Fructose-1,6-bisphosphatase is allosterically inhibited by fructose-6-phosphate in a sigmoidal fashion, allowing a fine control of the enzyme by its product.
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Affiliation(s)
- A Gardemann
- Institut für Biochemie der Pflanze der Universität Göttingen, Untere Karspüle 2, D-3400, Göttingen, Federal Republic of Germany
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Gerbling KP, Steup M, Latzko E. Fructose 1,6-Bisphosphatase Form B from Synechococcus leopoliensis Hydrolyzes both Fructose and Sedoheptulose Bisphosphate. PLANT PHYSIOLOGY 1986; 80:716-20. [PMID: 16664691 PMCID: PMC1075189 DOI: 10.1104/pp.80.3.716] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The substrate specificity of purified fructose bisphosphatase form B from Synechococcus leopoliensis (EC 3.1.3.11; cf. K-P Gerbling, M Steup, E Latzko 1985 Eur J Biochem 147: 207-215) has been investigated. Of the phosphate esters tested only fructose 1,6-bisphosphate and sedoheptulose 1,7-bisphosphate were hydrolyzed by the enzyme. Both sugar bisphosphates were cleaved at the carbon 1-ester. Fructose- and sedoheptulose bisphosphate stabilized the activated (i.e. tetrameric) state of the enzyme and prevented a slow inactivation that is observed in the absence of sugar bisphosphates. With the activated enzyme, kinetic constants (half-saturating substrate concentrations, maximal reaction velocity, and the catalytical constant) were similar for both fructose- and sedoheptulose bisphosphate. The data suggest that fructose bisphosphatase form B from Synechococcus leopoliensis can catalyze both bisphosphatase reactions within the reductive pentose phosphate cycle.
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Affiliation(s)
- K P Gerbling
- Botanisches Institut der Westfälischen Wilhelms-Universität, Schlossgarten 3, D-4400 Münster, Federal Republic of Germany
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24
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Soulié JM, Buc J, Rivière M, Ricard J. Equilibrium binding of thioredoxin fB to chloroplastic fructose bisphosphatase. Evidence for a thioredoxin site distinct from the active site. EUROPEAN JOURNAL OF BIOCHEMISTRY 1985; 152:565-8. [PMID: 2996894 DOI: 10.1111/j.1432-1033.1985.tb09232.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Thioredoxin fB, the protein activator of chloroplastic fructose 1,6-bisphosphatase, strongly binds its target enzyme with a stoichiometry of one protein dimer per enzyme tetramer. The thioredoxin binding site is distinct from the active site and the dissociation constant of the protein-enzyme complex has the extremely small value of 769 nM at pH 7.5. This interaction involves both ionic and hydrophobic contributions and is enhanced by a pH increase from 7 to 8. These results suggest that the above molecular properties may be involved in the light activation of chloroplastic fructose bisphosphatase.
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25
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Leegood RC. Regulation of photosynthetic CO2-pathway enzymes by light and other factors. PHOTOSYNTHESIS RESEARCH 1985; 6:247-259. [PMID: 24442923 DOI: 10.1007/bf00049281] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/1984] [Indexed: 06/03/2023]
Abstract
The regulatory properties of enzymes of the pathway of CO2 fixation are discussed in relation to changes in regulatory parameters with changing light, CO2 and temperature.
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Affiliation(s)
- R C Leegood
- Research Institute for Photosynthesis, Department of Botany, University of Sheffield, S10 2TN, Sheffield, UK
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26
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Marques IA, Anderson LE. Changing Kinetic Properties of Fructose-1,6-bisphosphatase from Pea Chloroplasts during Photosynthetic Induction. PLANT PHYSIOLOGY 1985; 77:807-10. [PMID: 16664142 PMCID: PMC1064610 DOI: 10.1104/pp.77.4.807] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
After dark-light transitions, there is a delay in photosynthetic CO(2) fixation by isolated pea chloroplasts in the range of some minutes. In order to assess the physiological significance of light modulation of enzyme activity in the control of induction, we made estimates of the kinetic parameters of fructose-1,6-bisphosphatase immediately upon release from pea chloroplasts in the dark and after illumination for various time periods. The Michaelis constant for fructose-1,6-bisphosphate decreased and maximal velocities increased during induction. It seems likely that light activation of this enzyme is one of the factors contributing to the overcoming of the lag period in photosynthetic CO(2) fixation.
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Affiliation(s)
- I A Marques
- Department of Biological Sciences, University of Illinois at Chicago, Box 4348, Chicago, Illinois 60680
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27
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Gontero B, Meunier J, Ricard J. On the activation of two chlorplastic phosphatases by fructose bisphosphate, sedoheptulose bisphosphate and magnesium. ACTA ACUST UNITED AC 1984. [DOI: 10.1016/0304-4211(84)90168-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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28
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Chueca A, Lázaro JJ, Gorgé JL. Light-Induced Nuclear Synthesis of Spinach Chloroplast Fructose-1,6-bisphosphatase. PLANT PHYSIOLOGY 1984; 75:539-41. [PMID: 16663662 PMCID: PMC1066951 DOI: 10.1104/pp.75.3.539] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Etiolated spinach (Spinacia oleracea L. var Winter Giant) seedlings show a residual photosynthetic fructose-1,6-bisphosphatase activity, which sharply rises under illumination. This increase in activity is due to a light-induced de novo synthesis, as it has been demonstrated by enzyme labeling experiments with (2)H(2)O and [(35)S]methionine. The rise of bisphosphatase activity under illumination is strongly inhibited by cycloheximide, but not by the 70S ribosome inhibitor lincocin, which shows the nuclear origin of this chloroplastic enzyme.
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Affiliation(s)
- A Chueca
- Unidad de Bioquímica Vegetal, Estación Experimental del Zaidín (CSIC), Granada, Spain
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29
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Rosa L, Whatley FR. Conditions Required for the Rapid Activation In Vitro of the Chloroplast Fructose-1,6-bisphosphatase. PLANT PHYSIOLOGY 1984; 75:131-7. [PMID: 16663557 PMCID: PMC1066848 DOI: 10.1104/pp.75.1.131] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Conditions required for the reductive activation of purified, spinach chloroplast fructose-1,6-bisphosphatase (EC 3.1.3.11) have been determined in vitro. Full reductive activation was observed only when fructose-1,6-bisphosphate and Mg(2+) were present at the same time as the reducing agent (dithiothreitol). Reduction in the absence either of fructose-1,6-bisphosphate or of Mg(2+) slowly and irreversibly inactivated the enzyme. The concentration of fructose-1,6-bisphosphate that must be present during reduction for maximum activation depends upon the divalent cation present: it is highest with Mg(2+), lower with Ca(2+), and lowest when both Mg(2+) and Ca(2+) are present. A scheme for the reductive activation and inactivation of the enzyme is presented.
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Affiliation(s)
- L Rosa
- Botany School, University of Oxford, South Parks Road, Oxford OX1 3RA, United Kingdom
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30
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Buc J, Rivière M, Gontero B, Sauve P, Meunier JC, Ricard J. Affinity chromatography, on fructose-bisphosphatase-Sepharose, of two chloroplastic thioredoxins F. Purification and comparative molecular properties. EUROPEAN JOURNAL OF BIOCHEMISTRY 1984; 140:199-202. [PMID: 6323180 DOI: 10.1111/j.1432-1033.1984.tb08086.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A new method of purification of chloroplastic thioredoxins has been presented. This method is based on affinity chromatography on fructose-bisphosphatase--Sepharose columns. Two thioredoxin, fA and fB, may be extracted and purified to homogeneity from the same leaf extract. Whereas fA is monomeric and has an Mr of 11 400 +/- 500, fB is dimeric with an Mr of 18 000 +/- 600. The dimer dissociates in two halves in the ultracentrifuge under the effect of high pressures. Raising the ionic strength results in the same effect. Thioredoxins fA and fB activate to similar extents chloroplastic fructose bisphosphatase and NADP--malate dehydrogenase. Chloroplastic sedoheptulose bisphosphatase is activated by thioredoxin fB but not by thioredoxin fA.
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31
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Woodrow IE, Murphy DJ, Walker DA. Regulation of photosynthetic carbon metabolism. The effect of inorganic phosphate on stromal sedoheptulose-1,7-bisphosphatase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1983; 132:121-3. [PMID: 6301819 DOI: 10.1111/j.1432-1033.1983.tb07335.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The activation and steady-state kinetics of wheat chloroplast sedoheptulose-1,7-bisphosphatase at several concentrations of inorganic phosphate are examined. Inorganic phosphate competitively inhibits substrate binding to both the active and inactive forms of the enzyme and reduces the rate of enzyme activation. Modulation of the apparent Km of sedoheptulose-1,7-bisphosphatase and fructose-1,6-bisphosphatase for their substrates by inorganic phosphate is discussed in terms of the control of intermediate pool sizes in the reductive pentose phosphate pathway and of the flux of fixed carbon towards starch synthesis or export from the chloroplast.
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32
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Law MY, Charles SA, Halliwell B. Glutathione and ascorbic acid in spinach (Spinacia oleracea) chloroplasts. The effect of hydrogen peroxide and of Paraquat. Biochem J 1983; 210:899-903. [PMID: 6307273 PMCID: PMC1154305 DOI: 10.1042/bj2100899] [Citation(s) in RCA: 424] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The stroma of spinach chloroplasts contains ascorbic acid and glutathione at millimolar concentrations. [Reduced glutathione]/[oxidized glutathione] and [ascorbate]/[dehydroascorbate] ratios are high under both light and dark conditions and no evidence for a role of oxidized glutathione or dehydroascorbate in the dark-deactivation of fructose bisphosphatase could be obtained. Addition of H2O2 to chloroplasts in the dark decreases the above ratios, an effect that is reversed on illumination. Addition of Paraquat to illuminated chloroplasts caused a rapid oxidation of reduced glutathione and ascorbate, and apparent loss of dehydroascorbate. Paraquat rapidly inactivated fructose bisphosphatase activity, as assayed under physiological conditions.
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33
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Hertig CM, Wolosiuk RA. Studies on the hysteretic properties of chloroplast fructose-1,6-bisphosphatase. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(18)33147-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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34
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Leegood RC, Walker DA. Regulation of fructose-1,6-bisphosphatase activity in leaves. PLANTA 1982; 156:449-456. [PMID: 24272658 DOI: 10.1007/bf00393316] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/1982] [Accepted: 08/03/1982] [Indexed: 06/02/2023]
Abstract
Fructose-1,6-bisphosphatase (EC 3.1.3.11) activity increased markedly (greater than 10-fold) upon illumination of wheat leaves. Darkening caused a relatively slow but complete reversal of light activation. The effects of O2 and CO2 concentration and light intensity on fructose-bisphosphatase activation were measured. In ratelimiting light, 2% O2 stimulated enzyme activity, whereas varying the CO2 concentration had little effect. In saturating light, lowering the oxygen tension had no effect, but CO2 at near-saturating concentrations for photosynthesis inhibited enzyme activity. Dark inactivation of the enzyme was completely prevented by incubation of leaves in N2, but was facilitated by O2, indicating that O2 is the major oxidant in darkened leaves. It is argued that while fructose bisphosphatase is redox-regulated in leaves, modulation of enzyme activity by this mechanism is unlikely to contribute to the regulation of CO2 fixation in leaves.
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Affiliation(s)
- R C Leegood
- ARC Research Group on Photosynthesis, Botany Department, University of Sheffield, S10 2TN, Sheffield, UK
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35
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Alscher-Herman R. Chloroplast alkaline fructose 1,6-bisphosphatase exists in a membrane-bound form. PLANT PHYSIOLOGY 1982; 70:728-34. [PMID: 16662565 PMCID: PMC1065760 DOI: 10.1104/pp.70.3.728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
An alkaline fructose 1,6-bisphosphatase activity associated with soybean (Glycine max cv Beeson) chloroplasts appears to be membrane-bound. The pH optimum of the membrane-associated activity corresponds to that found for activity associated with the stroma. Illumination of washed thylakoids results in an increase in alkaline fructose 1,6-bisphosphatase activity in the absence of any added stromal factors. Exposure to pH 8.0 results in a partial release of enzyme activity from the membrane. The activation status of the enzyme does not appear to alter its association with the membrane.
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36
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Gottschalk ME, Chatterjee T, Edelstein I, Marcus F. Studies on the mechanism of interaction of fructose 2,6-bisphosphate with fructose-1,6-bisphosphatase. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34290-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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37
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Kelly GJ, Zimmermann G, Latzko E. Fructose-bisphosphatase from spinach leaf chloroplast and cytoplasm. Methods Enzymol 1982; 90 Pt E:371-8. [PMID: 6296613 DOI: 10.1016/s0076-6879(82)90158-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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38
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Charles SA, Halliwell B. Light activation of fructose bisphosphatase in photosynthetically competent pea chloroplasts. Biochem J 1981; 200:357-63. [PMID: 6280684 PMCID: PMC1163543 DOI: 10.1042/bj2000357] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The fructose bisphosphatase (EC 3.1.3.11) activity of type A chloroplasts isolated from young (9-day-old) pea (Pisum sativum var. Progress no. 9) plants, assayed at physiological pH, substrate and Mg2+ concentrations, increased rapidly on illumination. The enzyme activity detected was more than sufficient to account for observed rates of Co2 fixation both during the induction period and during steady-state CO2 fixation, whether or not dihydroxyacetone phosphate had been added to the preparation. Omission of catalase from the suspension medium had no effect. On switching off the light, CO2 fixation by the chloroplasts ceased at once, yet fructose bisphosphatase activity decreased much more slowly. Changes in enzyme activity were much less marked if assays were conducted at 3 mM substrate and 10 mM-Mg2+. Chloroplasts from older (13--20-day-old) peas only fixed CO2 rapidly if catalase was present in the assay medium. The fructose bisphosphatase activity detected under physiological assay conditions was again more than sufficient to account for observed rates of Co2 fixation. In the presence of added dihydroxyacetone phosphate, however, the rate of Co2 fixation appeared to be determined by the rate of light activation of fructose bisphosphatase. In general, the rates of Co2 fixation and enzyme activation, and the final enzyme activity achieved, decreased markedly with increasing age of the plants. The role of light activation of fructose bisphosphatase as a means of controlling the rate of CO2 fixation in pea chloroplasts is discussed.
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Soulié JM, Buc J, Meunier JC, Pradel J, Ricard J. Molecular properties of chloroplastic thioredoxin f and the photoregulation of the activity of fructose 1,6-bisphosphatase. EUROPEAN JOURNAL OF BIOCHEMISTRY 1981; 119:497-502. [PMID: 6273161 DOI: 10.1111/j.1432-1033.1981.tb05635.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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40
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Laing WA, Stitt M, Heldt HW. Control of CO2 fixation. Changes in the activity of ribulosephosphate kinase and fructose- and sedoheptulose-bisphosphatase in chloroplasts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1981. [DOI: 10.1016/0005-2728(81)90174-2] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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41
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Pla A, Lopez-Gorge J. Thioredoxin/fructose-1,6-bisphosphatase affinity in the enzyme activation by the ferredoxin-thioredoxin system. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 636:113-8. [PMID: 6269592 DOI: 10.1016/0005-2728(81)90082-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In this work we analyze the affinity relationship between photosynthetic fructose-1,6-bisphosphatase and ferredoxin and thioredoxin from spinach leaves, two components of the proposed light-activation system of this enzyme, using affinity techniques on ferredoxin- and thioredoxin-Sepharose columns. Oxidized and reduced ferredoxin did not show enzyme affinity, whereas thioredoxin, both the oxidized and the dithiothreitol-reduced form, exhibited a strong bisphosphatase affinity at pH 7.5; this thioredoxin/enzyme affinity appears diminished at pH 8.2. When the affinity experiments were performed in the presence of 5 mM Mg2+, only 30% and 12% of the bisphosphatase remained bound to the thioredoxin-Sepharose at pH 7.5 and 8.0, respectively; these percentages were reduced to 6% when the Mg2+ concentration increased to 10 mM. These results suggest that a rise of stromal pH and Mg2+ concentration can account for a loosening of the thioredoxin/bisphosphatase linkage, which could be of physiological significance in the dark-light transition. Studies on the nature of the chemical groups responsible for the affinity have shown that the thioredoxin/bisphosphatase linkage is concerned with the existence of hydrophobic clusters. We have found no difference in the behaviour of the chloroplastic thioredoxins f and m, and the cytoplasmic ones cf and cm. These results support the existence of an in vivo thioredoxin/fructose-1,6-bisphosphatase interaction, in accordance with the light-activation mechanism by the ferredoxin-thioredoxin system.
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42
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Charles SA, Halliwell B. The role of calcium ions and the thioredoxin system in regulation of spinach chloroplast fructosebisphosphatase. Cell Calcium 1981. [DOI: 10.1016/0143-4160(81)90037-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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43
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Charles SA, Halliwell B. Light activation of fructose bisphosphatase in isolated spinach chloroplasts and deactivation by hydrogen peroxide : A physiological role for the thioredoxin system. PLANTA 1981; 151:242-246. [PMID: 24301849 DOI: 10.1007/bf00395175] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/1980] [Accepted: 10/15/1980] [Indexed: 06/02/2023]
Abstract
Spinach chloroplast fructose bisphosphatase (EC 3.1.3.11.) exists in both oxidised and reduced forms. Only the latter has the kinetic properties that allow it to function at physiological concentrations of fructose 1,6-bisphosphate and Mg(2+). Illumination of freshly prepared type A chloroplasts causes a conversion of oxidised to reduced enzyme. The rate of this conversion does not limit the rate of CO2 fixation. In the dark the reduced enzyme partially reverts back to the oxidised form. If catalase is omitted from the reaction medium the rate of CO2 fixation by chloroplasts is decreased and seems to be limited by the rate of conversion of the enzyme to the reduced form. The physiological significance of the light dependent generation of dithiol compounds (such as thioredoxin) within chloroplasts is discussed.
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Affiliation(s)
- S A Charles
- Department of Biochemistry, University of London, King's College, Strand, WC2R 2LS, London, UK
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44
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Hertig C, Wolosiuk RA. A dual effect of Ca2+ on chloroplast fructose-1,6-bisphosphatase. Biochem Biophys Res Commun 1980; 97:325-33. [PMID: 6257242 DOI: 10.1016/s0006-291x(80)80171-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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45
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Charles SA, Halliwell B. Effect of hydrogen peroxide on spinach (Spinacia oleracea) chloroplast fructose bisphosphatase. Biochem J 1980; 189:373-6. [PMID: 6257234 PMCID: PMC1162009 DOI: 10.1042/bj1890373] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thiol-treated spinach (Spinacia oleracea) chloroplast fructose bisphosphatase (EC 3.1.3.11) is severely inhibited by H2O2, whereas the freshly purified enzyme is little affected. Dithiothreitol reverses inhibition by H2O2, indicating that essential thiol groups are oxidized during H2O2 inactivation. A new role for the dithiol and thioredoxin systems that are operative in illuminated chloroplasts is proposed.
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46
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Charles SA, Halliwell B. Action of calcium ions on spinach (Spinacia oleracea) chloroplast fructose bisphosphatase and other enzymes of the Calvin cycle. Biochem J 1980; 188:775-9. [PMID: 6258561 PMCID: PMC1161961 DOI: 10.1042/bj1880775] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thiol-treated spinach (Spinacia oleracea) chloroplast fructose bisphosphatase is powerfully inhibited by Ca2+ non-competitively with respect to its substrate, fructose 1,6-bisphosphate. 500 microM-Ca2+ causes virtually complete inhibition and the Ki is 40 microM. Severe inhibition of sedoheptulose bisphosphatase is also caused by Ca2+. A role for Ca2+ in regulation of the Calvin cycle in spinach chloroplasts is proposed.
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