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Louise E. Anderson - One of the best experts on this subject based on the ideXlab platform.
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Enzyme co-localization in pea leaf chloroplasts: glyceraldehyde-3-P dehydrogenase, triose-P isomerase, aldolase and sedoheptulose Bisphosphatase
Photosynthesis Research, 2005Co-Authors: Louise E. Anderson, Nandita Gatla, Andrew A. CarolAbstract:Nearest neighbor analysis of immunocytolocalization experiments indicates that the enzymes glyceraldehyde-3-P dehydrogenase, triose-P isomerase and aldolase are located close to one another in the pea leaf chloroplast stroma, and that aldolase is located close to sedoheptulose Bisphosphatase. Direct transfer of the triose phosphates between glyceraldehyde-3-P dehydrogenase and triose-P isomerase, and from glyceraldehyde-3-P dehydrogenase and triose-P isomerase to aldolase, is then a possibility, as is direct transfer of sedoheptulose bisphosphate from aldolase to sedoheptulose Bisphosphatase. Spatial organization of these enzymes may be important for efficient CO_2 fixation in photosynthetic organisms. In contrast, there is no indication that Fructose Bisphosphatase is co-localized with aldolase, and direct transfer of Fructose bisphosphate from aldolase to Fructose Bisphosphatase seems unlikely.
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Enzyme co-localization in the pea leaf cytosol: 3-P-glycerate kinase, glyceraldehyde-3-P dehydrogenase, triose-P isomerase and aldolase
Plant Science, 2005Co-Authors: Louise E. Anderson, Andrew A. CarolAbstract:Abstract Nearest neighbor analysis of immunocytolocalization experiments indicates that the Embden–Meyerhof pathway enzymes aldolase, triose-P isomerase, glyceraldehyde-3-P dehydrogenase and P-glycerate kinase are located close to one another in the pea leaf cytosol. Direct transfer of the triose phosphates between aldolase, glyceraldehyde-3-P dehydrogenase and triose-P isomerase, direct transfer of glyceraldehyde-3-P between glyceraldehyde-3-P dehydrogenase and triose-P isomerase, and direct transfer of 1,3-P2-glycerate between glyceraldehyde-3-P dehydrogenase and P-glycerate kinase is then a possibility in the plant cytosol. In contrast, there is no indication that Fructose Bisphosphatase is co-localized with aldolase, and it unlikely that Fructose bisphosphate is channeled from aldolase to Fructose Bisphosphatase in this system.
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Mass Spectrometric Evidence for an Alternate Disulfide Bond in Chloroplast Fructose Bisphosphatase.
Photosynthesis research, 2004Co-Authors: J. Throck Watson, Fred J. Stevens, Rayan Yousefzai, Louise E. AndersonAbstract:Mass mapping analysis based on cyanylation (CN) of the protein and CN-induced cleavage indicates that all three cysteine residues in the insertion into the light-activated pea leaf chloroplast Fructose Bisphosphatase (E.C. 3.1.3.11) are able to participate in disulfide bond formation. There is a major peak in the mass spectrum of the cleavage products indicating that Cys173 forms a disulfide bond with Cys153, consistent with the structure of the oxidized enzyme in PDB files 1d9q and 1dcu, and a minor peak indicating that Cys173 forms an alternate disulfide bond with Cys178. The Cys173–Cys178 disulfide bond was not apparent in the available crystal structures.
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SEVEN ENZYMES OF CARBON METABOLISM, INCLUDING THREE CALVIN CYCLE ISOZYMES, ARE PRESENT IN THE SECONDARY CELL WALL THICKENINGS OF THE DEVELOPING XYLEM TRACHEARY ELEMENTS IN PEA LEAVES
International Journal of Plant Sciences, 2004Co-Authors: Louise E. Anderson, Andrew A. CarolAbstract:Antibodies directed against chloroplast aldolase and chloroplast Fructose Bisphosphatase and against cytosolic Fructose Bisphosphatase, cytosolic P‐glycerate kinase, and cytosolic glyceraldehyde‐3‐P dehydrogenase recognize antigens in the secondary cell wall thickenings in the developing xylem tracheary elements in pea (Pisum sativum L.) leaf mesophyll cells. The isozyme specificity indicates sorting and selection during cell death and xylem formation. Antibodies directed against ADP‐glucose pyrophosphorylase, sedoheptulose Bisphosphatase, triose‐P isomerase, and the photosynthetic electron transport component plastocyanin also recognize secondary cell wall components. It seems possible that these proteins are being recycled and put to some alternate use in the developing xylem.
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The cytosolic Fructose Bisphosphatase of Brassica napus contains a new potential regulatory disulfide and is redox-sensitive
Plant Science, 1997Co-Authors: Louise E. Anderson, Sonia C Nehrlich, Melanie H Hill, Fred J. StevensAbstract:Abstract The deduced amino acid sequences of the Brassica napus and sugar cane ( Saccharum sp.) cytosolic Fructose Bisphosphatases (EC 3.1.3.11) have appeared recently. When the three-dimensional structure of the Brassica napus Bisphosphatase was modeled residue 92, previously identified as a potential redox-sensitive regulatory cysteine in the cytosolic enzymes from potato, sugarbeet and spinach [L.E. Anderson, et al., Planta 196 (1995) 118–124], was a serine. (Numbering according to Protein Data Bank entry 4FBP.) Instead there is a Cys at position 110, close enough to Cys-114, the second member of the potential regulatory cysteine pair in the other cytosolic Fructose Bisphosphatases, to suggest the possibility of disulfide bond formation and the enzyme is redox-sensitive. The sugar cane enzyme, like the other three cytosolic Fructose Bisphosphatases, contains Cys-92 and Cys-114. It also is redox-sensitive. Apparently a disulfide anywhere in the region of Cys-114, -92 and -110 can function in the redox-modulation of the activity of this enzyme.
Gabriele M Siegel - One of the best experts on this subject based on the ideXlab platform.
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Stimulation of spinach (Spinacia oleracea) chloroplast Fructose‐1,6‐Bisphosphatase by mercuric ions
FEBS letters, 1997Co-Authors: Anthony R. Ashton, Gabriele M SiegelAbstract:Chloroplast Fructose-1,6-Bisphosphatase can exist in an active reduced form or a less active oxidised form. Oxidised Fructose Bisphosphatase from spinach (Spinacia oleracea) could be stimulated up to many hundred-fold by 0.1 mM HgCl2 whereas Fructose Bisphosphatases from rabbit, yeast, a non-chloroplast enzyme from spinach and the reduced chloroplast enzyme were only inhibited by HgCl2. Stimulation of the enzyme was maximal at pH 8.0 and low magnesium concentrations where the oxidised enzyme normally has little activity.
Loranne Agius - One of the best experts on this subject based on the ideXlab platform.
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contributions of glucokinase and phosphofructokinase 2 Fructose Bisphosphatase 2 to the elevated glycolysis in hepatocytes from zucker fa fa rats
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2007Co-Authors: Victoria A Payne, Catherine Arden, Alex J Lange, Loranne AgiusAbstract:The insulin-resistant Zucker fa/fa rat has elevated hepatic glycolysis and activities of glucokinase and phosphofructokinase-2/Fructose Bisphosphatase-2 (PFK2). The latter catalyzes the formation a...
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Glucokinase regulatory protein is associated with mitochondria in hepatocytes
FEBS Letters, 2006Co-Authors: Catherine Arden, Simone Baltrusch, Loranne AgiusAbstract:Abstract The association of glucokinase with liver mitochondria has been reported [Danial et al. (2003) BAD and glucokinase reside in a mitochondrial complex that integrates glycolysis and apoptosis. Nature 424, 952–956]. We confirmed association of glucokinase immunoreactivity with rat liver mitochondria using Percoll gradient centrifugation and demonstrated its association with the 68 kDa regulatory protein (GKRP) but not with the binding protein phosphofructokinase-2/Fructose Bisphosphatase-2. Substrates and glucagon induced adaptive changes in the mitochondrial glucokinase/GKRP ratio suggesting a regulatory role for GKRP. Combined with previous observations that GKRP overexpression partially inhibits glycolysis [de la Iglesia et al. (2000) The role of the regulatory protein of glucokinase in the glucose sensory mechanism of the hepatocyte. J. Biol. Chem. 275, 10597–10603] these findings suggest that there may be distinct glycolytic pools of glucokinase.
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dual role of phosphofructokinase 2 Fructose Bisphosphatase 2 in regulating the compartmentation and expression of glucokinase in hepatocytes
Diabetes, 2005Co-Authors: Victoria A Payne, Catherine Arden, Alex J Lange, Loranne AgiusAbstract:Hepatic glucokinase is regulated by a 68-kDa regulatory protein (GKRP) that is both an inhibitor and nuclear receptor for glucokinase. We tested the role of 6-phosphofructo-2-kinase/Fructose-2,6-Bisphosphatase (PFK2) in regulating glucokinase compartmentation in hepatocytes. PFK2 catalyzes formation or degradation of the regulator of glycolysis Fructose 2,6-bisphosphate (Fructose 2,6-P 2 ), depending on its phosphorylation state (ser-32), and is also a glucokinase-binding protein. Incubation of hepatocytes at 25 mmol/l glucose causes translocation of glucokinase from the nucleus to the cytoplasm and an increase in Fructose 2,6-P 2 . Glucagon caused phosphorylation of PFK2-ser-32, lowered the Fructose 2,6-P 2 concentration, and inhibited glucose-induced translocation of glucokinase. These effects of glucagon were reversed by expression of a kinase-active PFK2 mutant (S32A/H258A) that overrides the suppression of Fructose 2,6-P 2 but not by overexpression of wild-type PFK2. Overexpression of PFK2 potentiated glucokinase expression in hepatocytes transduced with an adenoviral vector–encoding glucokinase by a mechanism that does not involve stabilization of glucokinase protein from degradation. It is concluded that PFK2 has a dual role in regulating glucokinase in hepatocytes: it potentiates glucokinase protein expression by posttranscriptional mechanisms and favors its cytoplasmic compartmention. Thus, it acts in a complementary mechanism to GKRP, which also regulates glucokinase protein expression and compartmentation.
Fred J. Stevens - One of the best experts on this subject based on the ideXlab platform.
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Mass Spectrometric Evidence for an Alternate Disulfide Bond in Chloroplast Fructose Bisphosphatase.
Photosynthesis research, 2004Co-Authors: J. Throck Watson, Fred J. Stevens, Rayan Yousefzai, Louise E. AndersonAbstract:Mass mapping analysis based on cyanylation (CN) of the protein and CN-induced cleavage indicates that all three cysteine residues in the insertion into the light-activated pea leaf chloroplast Fructose Bisphosphatase (E.C. 3.1.3.11) are able to participate in disulfide bond formation. There is a major peak in the mass spectrum of the cleavage products indicating that Cys173 forms a disulfide bond with Cys153, consistent with the structure of the oxidized enzyme in PDB files 1d9q and 1dcu, and a minor peak indicating that Cys173 forms an alternate disulfide bond with Cys178. The Cys173–Cys178 disulfide bond was not apparent in the available crystal structures.
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The cytosolic Fructose Bisphosphatase of Brassica napus contains a new potential regulatory disulfide and is redox-sensitive
Plant Science, 1997Co-Authors: Louise E. Anderson, Sonia C Nehrlich, Melanie H Hill, Fred J. StevensAbstract:Abstract The deduced amino acid sequences of the Brassica napus and sugar cane ( Saccharum sp.) cytosolic Fructose Bisphosphatases (EC 3.1.3.11) have appeared recently. When the three-dimensional structure of the Brassica napus Bisphosphatase was modeled residue 92, previously identified as a potential redox-sensitive regulatory cysteine in the cytosolic enzymes from potato, sugarbeet and spinach [L.E. Anderson, et al., Planta 196 (1995) 118–124], was a serine. (Numbering according to Protein Data Bank entry 4FBP.) Instead there is a Cys at position 110, close enough to Cys-114, the second member of the potential regulatory cysteine pair in the other cytosolic Fructose Bisphosphatases, to suggest the possibility of disulfide bond formation and the enzyme is redox-sensitive. The sugar cane enzyme, like the other three cytosolic Fructose Bisphosphatases, contains Cys-92 and Cys-114. It also is redox-sensitive. Apparently a disulfide anywhere in the region of Cys-114, -92 and -110 can function in the redox-modulation of the activity of this enzyme.
Andrew A. Carol - One of the best experts on this subject based on the ideXlab platform.
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Enzyme co-localization in pea leaf chloroplasts: glyceraldehyde-3-P dehydrogenase, triose-P isomerase, aldolase and sedoheptulose Bisphosphatase
Photosynthesis Research, 2005Co-Authors: Louise E. Anderson, Nandita Gatla, Andrew A. CarolAbstract:Nearest neighbor analysis of immunocytolocalization experiments indicates that the enzymes glyceraldehyde-3-P dehydrogenase, triose-P isomerase and aldolase are located close to one another in the pea leaf chloroplast stroma, and that aldolase is located close to sedoheptulose Bisphosphatase. Direct transfer of the triose phosphates between glyceraldehyde-3-P dehydrogenase and triose-P isomerase, and from glyceraldehyde-3-P dehydrogenase and triose-P isomerase to aldolase, is then a possibility, as is direct transfer of sedoheptulose bisphosphate from aldolase to sedoheptulose Bisphosphatase. Spatial organization of these enzymes may be important for efficient CO_2 fixation in photosynthetic organisms. In contrast, there is no indication that Fructose Bisphosphatase is co-localized with aldolase, and direct transfer of Fructose bisphosphate from aldolase to Fructose Bisphosphatase seems unlikely.
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Enzyme co-localization in the pea leaf cytosol: 3-P-glycerate kinase, glyceraldehyde-3-P dehydrogenase, triose-P isomerase and aldolase
Plant Science, 2005Co-Authors: Louise E. Anderson, Andrew A. CarolAbstract:Abstract Nearest neighbor analysis of immunocytolocalization experiments indicates that the Embden–Meyerhof pathway enzymes aldolase, triose-P isomerase, glyceraldehyde-3-P dehydrogenase and P-glycerate kinase are located close to one another in the pea leaf cytosol. Direct transfer of the triose phosphates between aldolase, glyceraldehyde-3-P dehydrogenase and triose-P isomerase, direct transfer of glyceraldehyde-3-P between glyceraldehyde-3-P dehydrogenase and triose-P isomerase, and direct transfer of 1,3-P2-glycerate between glyceraldehyde-3-P dehydrogenase and P-glycerate kinase is then a possibility in the plant cytosol. In contrast, there is no indication that Fructose Bisphosphatase is co-localized with aldolase, and it unlikely that Fructose bisphosphate is channeled from aldolase to Fructose Bisphosphatase in this system.
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SEVEN ENZYMES OF CARBON METABOLISM, INCLUDING THREE CALVIN CYCLE ISOZYMES, ARE PRESENT IN THE SECONDARY CELL WALL THICKENINGS OF THE DEVELOPING XYLEM TRACHEARY ELEMENTS IN PEA LEAVES
International Journal of Plant Sciences, 2004Co-Authors: Louise E. Anderson, Andrew A. CarolAbstract:Antibodies directed against chloroplast aldolase and chloroplast Fructose Bisphosphatase and against cytosolic Fructose Bisphosphatase, cytosolic P‐glycerate kinase, and cytosolic glyceraldehyde‐3‐P dehydrogenase recognize antigens in the secondary cell wall thickenings in the developing xylem tracheary elements in pea (Pisum sativum L.) leaf mesophyll cells. The isozyme specificity indicates sorting and selection during cell death and xylem formation. Antibodies directed against ADP‐glucose pyrophosphorylase, sedoheptulose Bisphosphatase, triose‐P isomerase, and the photosynthetic electron transport component plastocyanin also recognize secondary cell wall components. It seems possible that these proteins are being recycled and put to some alternate use in the developing xylem.
