Fructose 2,6-Bisphosphate as a Regulatory Metabolite in Plants

Huber, Steve

doi:10.1146/annurev.pp.37.060186.001313

Cited by 80 publications

(22 citation statements)

References 27 publications

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“…It should be noted that covalent regulation, such as phosphorylation of the type described for bifunctional liver 6-PFru-2-K/Fru-2,6-P2ase (12-15), has been invoked in leaves (2). The current finding that 6-PFru-2-K and Fru-2,6-P2ase are separate proteins in spinach and lettuce should prompt a reexamination of such a mechanism in plants.…”

Section: Discussionmentioning

confidence: 79%

“…Fructose 2,6-bisphosphate (Fru-2,6-P2), a regulatory metabolite localized in the cytosol of leaf cells, plays a central role in the coordination of starch synthesis taking place in the chloroplast and sucrose synthesis and breakdown taking place in the cytosol (1)(2)(3). The concentration of Fru-2,6-P2 is defined by the activities responsible for its synthesis and hydrolysis-namely, 6-phosphofructo-2-kinase (6-PFru-2-K; ATP:D-fructose-6-phosphate 2-phosphotransferase, EC 2.7.1.105) (Eq.…”

mentioning

confidence: 99%

“…2), 6-PFru-2-K fructose 6-phosphate + ATP : fructose 2,6-bisphosphate + ADP, [1] fructose 2,6-bisphosphate + H20 r2P fructose 6-phosphate + Pi. [2] Previous reports have demonstrated the presence of these activities in leaves (4)(5)(6)(7)(8) as well as sink tissues (9)(10)(11) and elucidated their regulation by key metabolites of the glycolytic and gluconeogenic pathways. In the earlier studies, 6-PFru-2-K and Fru-2,6-P2ase cochromatographed through several steps ofpurification, and it was suggested that the two activities may reside on a single protein, as has been shown for the bifunctional enzyme from liver and certain other mammalian tissues (12)(13)(14)(15).…”

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confidence: 99%

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Activities synthesizing and degrading fructose 2,6-bisphosphate in spinach leaves reside on different proteins

Macdonald

Cséke²,

Chou³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

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Activities catalyzing the synthesis and degradation of fructose 2,6-bisphosphate-6-phosphofructo-2-kinase (ATP:D-fructose-6-phosphate-2-phosphotransferase, EC 2.7.1.105) and fructose-2,6-bisphosphatase (D-fructose-2,6-bisphosphate 2-phosphohydrolase, EC 3.1.3.46)-were isolated from spinach leaves by an improved procedure and separated on the basis of both charge and molecular weight. The separated activities showed no detectable cross-contamination, indicating, in contrast to all previous data, that they are not present on a single bifunctional protein of the classical type in liver. The fructose-2,6-bisphosphatase-a newly discovered phosphatase enzyme-differed from previous mixed preparations by showing greater specificity but lower affinity for fructose 2,6-bisphosphate, greater sensitivity to inhibition by inorganic phosphate, and in being sensitive to inhibition by Mg2 . The 6-phosphofructo-2-kinase was found to be inhibited by low levels of inorganic pyrophosphate and, in addition, to be regulated by the metabolites described previously. Similar results were obtained with preparations from lettuce leaves. The results support the view that, through individual regulation of the activities catalyzing its synthesis and breakdown, cytosolic metabolites are key factors in controlling the fructose

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Section: Discussionmentioning

confidence: 79%

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confidence: 99%

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confidence: 99%

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Activities synthesizing and degrading fructose 2,6-bisphosphate in spinach leaves reside on different proteins

Macdonald

Cséke²,

Chou³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

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“…Pyrophosphate: D-fructose 6-phosphate I-phosphotransferase (PPi-PFK), which catalyzes reversively the formation of Fru-l,6-P 2 /Pi and Fru-6-P/PPi is known to occur in some microbes/,2) protists,3,4) and a wide range of plants, 5,6) and has been purified and characterized from Entamoeba histolytica,l) Propionibacterium sherman ii, 2) Euglena gracilis, 7) Tritrichomonas foetus,4) Trichomonas vaginalis,4) Isotricha prostoma,4) castor beans,8) cucumber seeds,9) wheat seeds,1°,l1) potato tubers,12,13) pineapple leaves, 14) spinach leaves,15) and soybean suspension culture cells. 16 ) Fru-2,6-P 2 is a novel metabolite which acts as a regulator in glycolysis and gluconeogenesis in mammalian tissues.…”

mentioning

confidence: 99%

Purification and Characterization of Pyrophosphate: D-Fructose 6-Phosphate 1-Phosphotransferase from Rice Seedlings

Enomoto

Ohyama

Kodama

1992

Bioscience, Biotechnology, and Biochemistry

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“…The chloroplastic FBPase is involved in the regeneration of ribulose bisphosphate (RuBP) as well as in the formation of precursors for chloroplastic starch synthesis. The cytosolic FBPase located in the cytosol of the mesophyll cells is a key enzyme in the sucrose biosynthetic pathway, catalyzing the first irreversible reaction in the conversion of triose-phosphate (triose-P) to sucrose (Huber 1986).…”

Section: Introductionmentioning

confidence: 99%

Cytosolic fructose-1,6-bisphosphatase: A key enzyme in the sucrose biosynthetic pathway

Daie

1993

Photosynth Res

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Fructose-1,6 bisphosphatase (FBPase) is a ubiquitous enzyme controlling a key reaction. In non-photosynthetic tissues, it regulates the rate of gluconeogenesis. In photosynthetic tissues, two FBPase isozymes (chloroplastic and cytosolic) play key roles in carbon assimilation and metabolism. The cytosolic FBPase is one of the regulatory enzymes in the sucrose biosynthetic pathway - its activity is regulated by both fine and coarse control mechanisms. Kinetic and allosteric properties of the plant cytosolic FBPase are remarkably similar to the mammalian and yeast FBPase, but differ greatly from those of the chloroplastic FBPase. Cytosolic FBPase is relatively conserved among various organisms both at amino acid and nucleotide sequence levels. There is slightly higher similarity between mammalian FBPase and plant cytosolic FBPase than there is between the two plant FBPases. Expression of plant cytosolic FBPase gene is developmentally regulated and appears to be coordinated with the expression of Rubisco and other carbon metabolism enzymes. Similar to the gluconeogenic FBPase, relatively rapid end product repression of FBPase gene occurs in plant. However, unlike the gluconeogenic FBPase, a concurrent decline in plant FBPase activity does not occur in response to increased end product levels. The physiological significance of FBPase gene repression, therefore, remains unclear in plants. Both expression and activity of the cytosolic FBPase are regulated by environmental factors such as light and drought conditions. Light-dependent modulation of FBPase activity in plants appears to involve some type of posttranslational modification. In addition to elucidating the exact nature of the presumed posttranslational modification, cloning of genomic and upstream sequences is needed before we fully understand the molecular regulation of the cytosolic FBPase in plants. Use of transgenic plants with altered rates of FBPase activity offers potential for enhanced crop productivity.

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Fructose 2,6-Bisphosphate as a Regulatory Metabolite in Plants

Cited by 80 publications

References 27 publications

Activities synthesizing and degrading fructose 2,6-bisphosphate in spinach leaves reside on different proteins

Activities synthesizing and degrading fructose 2,6-bisphosphate in spinach leaves reside on different proteins

Purification and Characterization of Pyrophosphate: D-Fructose 6-Phosphate 1-Phosphotransferase from Rice Seedlings

Cytosolic fructose-1,6-bisphosphatase: A key enzyme in the sucrose biosynthetic pathway

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