scholarly journals Spinach (Spinacia oleracea) chloroplast sedoheptulose-1,7-bisphosphatase. Activation and deactivation, and immunological relationship to fructose-1,6-bisphosphatase

1988 ◽  
Vol 253 (1) ◽  
pp. 243-248 ◽  
Author(s):  
F Cadet ◽  
J C Meunier
Keyword(s):  
Spinacia Oleracea ◽  
Calvin Cycle ◽  
Inhibitory Effect ◽  
Reducing Agents ◽  
Stable Complex ◽  
Dark Light ◽  
Sepharose Column ◽  
Fructose 1,6 Bisphosphatase ◽  
Immunological Relationship

In this paper we study activation by dithiothreitol and reduced thioredoxins and deactivation by oxidized thioredoxins f of sedoheptulose-1,7-bisphosphatase. The behaviour of the enzyme when chromatographed on a thioredoxin-Sepharose column is also described. The enzyme is autoxidizable upon removal of reducing agents, and is activated when reduced by any of the thioredoxins. This mechanism may allow the regulation of the Calvin cycle upon light-dark and dark-light transitions. The formation of a stable complex between enzyme and thioredoxin could explain the inhibitory effect of high thioredoxin concentrations. The use of immunological techniques shows that sedoheptulose-1,7-bisphosphatase and fructose-1,6-bisphosphatase are poorly related immunologically.

Substrate-Binding Isotherms of Spinach Chloroplastic Fructose-1,6-bisphosphatase and the Photoregulation of the Calvin Cycle

1981 ◽  
Vol 113 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Jean-Claude MEUNIER ◽  
Jean BUC ◽  
Jean-Michel SOULIE ◽  
Jacques PRADEL ◽  
Jacques RICARD
Keyword(s):  
Substrate Binding ◽  
Calvin Cycle ◽  
Binding Isotherms ◽  
Fructose 1,6 Bisphosphatase

scholarly journals Nuclear RanGAP Is Required for the Heterochromatin Assembly and Is Reciprocally Regulated by Histone H3 and Clr4 Histone Methyltransferase in Schizosaccharomyces pombe

2006 ◽  
Vol 17 (6) ◽  
pp. 2524-2536 ◽  
Author(s):  
Hitoshi Nishijima ◽  
Jun-ichi Nakayama ◽  
Tomoko Yoshioka ◽  
Ayumi Kusano ◽  
Hideo Nishitani ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Histone H3 ◽  
Inhibitory Effect ◽  
Stable Complex ◽  
Gtpase Activating Protein ◽  
Ran Gtpase ◽  
The Core ◽  
Trimeric Complex ◽  
Core Histones ◽  
Heterochromatin Assembly

Although the Ran GTPase-activating protein RanGAP mainly functions in the cytoplasm, several lines of evidence indicate a nuclear function of RanGAP. We found that Schizosaccharomyces pombe RanGAP, SpRna1, bound the core of histone H3 (H3) and enhanced Clr4-mediated H3-lysine 9 (K9) methylation. This enhancement was not observed for methylation of the H3-tail containing K9 and was independent of SpRna1–RanGAP activity, suggesting that SpRna1 itself enhances Clr4-mediated H3-K9 methylation via H3. Although most SpRna1 is in the cytoplasm, some cofractionated with H3. Sprna1ts mutations caused decreases in Swi6 localization and H3-K9 methylation at all three heterochromatic regions of S. pombe. Thus, nuclear SpRna1 seems to be involved in heterochromatin assembly. All core histones bound SpRna1 and inhibited SpRna1–RanGAP activity. In contrast, Clr4 abolished the inhibitory effect of H3 on the RanGAP activity of SpRna1 but partially affected the other histones. SpRna1 formed a trimeric complex with H3 and Clr4, suggesting that nuclear SpRna1 is reciprocally regulated by histones, especially H3, and Clr4 on the chromatin to function for higher order chromatin assembly. We also found that SpRna1 formed a stable complex with Xpo1/Crm1 plus Ran-GTP, in the presence of H3.

scholarly journals Action of calcium ions on spinach (Spinacia oleracea) chloroplast fructose bisphosphatase and other enzymes of the Calvin cycle

1980 ◽  
Vol 188 (3) ◽  
pp. 775-779 ◽  
Author(s):  
S A Charles ◽  
B Halliwell
Keyword(s):  
Calcium Ions ◽  
Spinacia Oleracea ◽  
Calvin Cycle ◽  
Complete Inhibition ◽  
Fructose Bisphosphatase ◽  
Spinach Chloroplasts ◽  
Fructose 1,6 Bisphosphate ◽  
Sedoheptulose Bisphosphatase

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.

scholarly journals On the Activation of Fructose-1,6-bisphosphatase of Spinach Chloroplasts and the Regulation of the Calvin Cycle

1981 ◽  
Vol 113 (3) ◽  
pp. 507-511 ◽  
Author(s):  
Jacques PRADEL ◽  
Jean-Michel SOULIE ◽  
Jean BUC ◽  
Jean-Claude MEUNIER ◽  
Jacques RICARD
Keyword(s):  
Calvin Cycle ◽  
Spinach Chloroplasts ◽  
Fructose 1,6 Bisphosphatase

scholarly journals Regulatory Properties of Apple Leaf Cytosolic Fructose-1,6-bisphosphatase

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 761C-761
Author(s):  
Rui Zhou* ◽  
Lailiang Cheng
Keyword(s):  
Enzyme Activity ◽  
Adenosine Monophosphate ◽  
Competitive Inhibitor ◽  
Inhibitory Effect ◽  
Carbon Partitioning ◽  
Dihydroxyacetone Phosphate ◽  
Saturation Curve ◽  
Fruit Species ◽  
Apparent Homogeneity ◽  
Fructose 1,6 Bisphosphatase

Cytosolic fructose-1,6-bisphosphatase (cytoFBPase) (EC 3.1.3.11) occupies a strategic site in sucrose synthesis and has been demonstrated to play a key role in carbon partitioning between sucrose and starch in non-sorbitol forming plants. In addition to sucrose and starch, Sorbitol is the primary photosynthetic end product in the leaves of many tree fruit species in the Rosaceae family. To understand the biochemical regulation of photosynthetic carbon partitioning between sorbitol, sucrose and starch in sorbitol synthesizing species, we purified cytoFB-Pase to apparent homogeneity from apple leaves. The enzyme was a homotetramer with a subunit mass of 37 kDa. It was highly specific for fructose-1,6-bisphosphate with a Km of 3.1 μm and a Vmax of 48 units/mg protein. Either Mg2+ or Mn2+ was required for its activity with a Km of 0.59 mm and 62 μM, respectively. Li+, Ca2+, Zn2+, Cu2+ and Hg2+ inhibited whereas Mn2+ enhanced the Mg2+-activated enzyme activity. Fructose-6-phosphate was found to be a mixed type inhibitor with a Ki of 0.47 mm. Fructose 2,6-bisphosphate (F2,6BP) competitively inhibited the enzyme activity and changed the substrate saturation curve from hyperbolic to sigmoidal. Adenosine monophosphate (AMP) was a non-competitive inhibitor for the enzyme. F2,6BP interacted with AMP to inhibit the enzyme in a synergistic way. Dihydroxyacetone phosphate did not have inhibitory effect on apple leaf cytosolic FBPase activity. Sorbitol increased the susceptibility of the enzyme to the inhibition by F1,6BP. The presence of sorbitol in the reaction mixture led to a reduction in the enzyme activity.

CO2 Fixation in Anabaena cylindrica

1982 ◽  
Vol 37 (3-4) ◽  
pp. 213-217 ◽  
Author(s):  
Günter Döhler
Keyword(s):  
Co2 Fixation ◽  
Calvin Cycle ◽  
Total Radioactivity ◽  
Nitrogen Atmosphere ◽  
Anabaena Cylindrica ◽  
Dark Light ◽  
Initial Fixation ◽  
Phosphoglyceric Acid ◽  
Cyanobacterium Anabaena ◽  
Glycolate Metabolism

Abstract The cyanobacterium Anabaena cylindrica grown in a nitrogen -free medium at + 25 °C was used for short-term 14C-kinetics experiments under different conditions. During the dark/light transients the initial fixation products were mainly sugar monophosphates and 3-phosphoglyceric acid (Calvin cycle intermediates), aspartate (10% of total radioactivity) and glycine/serine. Io­ doacetamide (0.01 м) caused an inhibition o f photosynthetic 14CO2 fixation and a 14C-in corpor­ation into aspartate, glutamate and 3-phosphoglyceric acid only. During dark 14CO2 assimilation labelling of these products could be measured, too. In a nitrogen atmosphere (N2 + 0.04 vol. % CO2) a strong labelling of sugar monophosphates mainly at the beginning o f photosynthetic period could be observed. In an oxygen atmosphere (100% O2) an enhanced label of aspartate and glycerate and a decreased radioactivity in sugar monophosphates were found. Our results were discussed with reference to the operating of a phosphoenolpyruvate carboxylation reaction be­ sides the Calvin cycle and to the glycolate metabolism.

Sedoheptulose-1,7-bisphosphate phosphatase activity of chloroplast fructose-1,6-bisphosphatase: identification of enzymes hydrolysing fructose-1,6-bisphosphate and sedoheptulose-1,7-bisphosphate in stromal extracts from chloroplasts of spinach (Spinaci

1998 ◽  
Vol 25 (5) ◽  
pp. 531 ◽  
Author(s):  
Anthony R. Ashton
Keyword(s):  
Phosphatase Activity ◽  
Spinacia Oleracea ◽  
Reduced Form ◽  
Fructose 1,6 Bisphosphatase ◽  
Fructose 1,6 Bisphosphate ◽  
Hydrolysis Of ◽  
Enzyme Species

The identity of enzymes present in soluble extracts of spinach(Spinacia oleracea) chloroplasts that are capable ofhydrolysing fructose-1,6-bisphosphate and sedoheptulose-1,7-bisphosphate hasbeen investigated using antibodies against purified spinach chloroplastfructose-1,6-bisphosphatase (EC 3.1.3.11). The activity of purifiedfructose-1,6-bisphosphatase, which can exist in a less active oxidised form ora more active reduced form as well as total fructose-1,6-bisphosphatase instromal extracts is inhibited completely by the antiserum. Apparently, only asingle enzyme, which can exist in an oxidised or reduced form, is responsiblefor hydrolysis of fructose-1,6-bisphosphate in the chloroplast. Purifiedchloroplast fructose-1,6-bisphosphatase can also exhibitsedoheptulose-1,7-bisphosphatase activity, but only when reduced. Oxidisedchloroplast stromal extracts contain little or nosedoheptulose-1,7-bisphosphatase activity whereas reduced extracts containsedoheptulose-1,7-bisphosphatase activity. Antiserum against fructose-1,6-bisphosphatase does not inhibit sedoheptulose-1,7-bisphosphatase activitydetectable at pH 8 or less with 2 mM Mg2+ butsubstantially inhibits (up to 60%) the sedoheptulose-1,7-bisphosphataseactivity at higher pH or Mg2+ concentration, i.e.conditions under which the chloroplast fructose-1,6-bisphosphatase exhibitssedoheptulose-1,7-bisphosphatase activity. Apparently, the chloroplast stromacontains at least two enzyme species capable of hydrolysingsedoheptulose-1,7-bisphosphate, a specific sedoheptulose-1,7-bispho-sphatase(EC 3.1.3.37) and the chloroplast fructose-1,6-bisphosphatase.

scholarly journals Disequilibrium evolution of Fructose-1,6-bisphosphatase gene family leads to their functional biodiversity in Gossypium species

2020 ◽  
Author(s):  
Qun Ge ◽  
Yànli Cūi ◽  
Jùnwén Lǐ ◽  
Jǔwǔ Gōng ◽  
Quánwěi Lú ◽  
...  
Keyword(s):  
Salt Stress ◽  
Gene Family ◽  
Cotton Fiber ◽  
Calvin Cycle ◽  
Purifying Selection ◽  
Fiber Development ◽  
Plant Responses ◽  
Cotton Fiber Development ◽  
Evolution Pattern ◽  
Fructose 1,6 Bisphosphatase

Abstract Background：Fructose-1,6-bisphosphatase (FBP) is a key enzyme in plant sucrose synthesis pathway in Calvin cycle and plays an important role in photosynthesis regulation in green plants. However, no systemic analysis of the FBPs has been reported in Gossypium species.Results：A total of 41 FBP genes from four Gossypium species were identified and analyzed. The FBP genes were assorted into two groups and 7 subgroups. The results revealed that FBP family genes were under a purifying selection pressure which rendered FBP family members a conserved evolution pattern and that there was no tandem and fragmental DNA duplication in FBP family genes. Collinearity analysis revealed that a FBP gene was located in the translocated DNA fragment and the whole FBP gene family was under a disequilibrium evolution pattern which led to a faster evolution progress of the members in G. barbadense and in At subgenome than those in the rest Gossypium species and in Dt subgenome, respectively of this study. Through RNA-seq analyses and qRT-PCR verifications, different FBP genes have diversified biological functions in cotton fiber development (2 genes in 0 DPA and 1DPA ovules and 4 genes in 20-25 DPA fibers), and in plant responses to Verticillium wilt onset (2 genes) and to salt stress (8 genes).Conclusion: The FBP gene family displayed disequilibrium evolution pattern in Gossypium species, which render them diversified functions affecting not only fiber development, but also responses to the Verticillium wilt and the salt stress. All the findings provided the foundation for further study of the function of the FBP genes in cotton fiber development and in environmental adaptability.

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