Sorbitol dehydrogenase is a cytosolic protein required for sorbitol metabolism in Arabidopsis thaliana

Sorbitol participates in the osmoregulation of several renal cells and has also been found in isolated inner medullary collecting duct (IMCD) cells in primary culture. Therefore, osmotic regulation and distribution of sorbitol and the key enzymes of sorbitol metabolism, aldose reductase and sorbitol dehydrogenase in the renal inner medulla, were investigated in vivo under various osmotic conditions (control, diuresis, antidiuresis). In homogenates of the renal inner medulla of Wistar rats, the sorbitol content correlated with the urine osmolarity [68 +/- 12 mumol/g protein (control), 28 +/- 9 mumol/g (diuresis), 110 +/- 15 mumol/g (antidiuresis)]. Similar results were obtained for the activity of aldose reductase (sorbitol synthesis) [25 +/- 4 U/g (control), 19 +/- 3 U/g (diuresis), and 48 +/- 7 U/g (antidiuresis)]. On the contrary, the activity of sorbitol dehydrogenase (sorbitol degradation) was significantly increased to 1.26 +/- 0.42 U/g under diuretic conditions vs. control (0.84 +/- 0.14 U/g, P < 0.05). These results demonstrate the correlation between the enzymes of sorbitol synthesis and sorbitol degradation in the intact inner medulla and the urine osmolarity in vivo. Whereas the aldose reductase activity was 2.3-fold enriched in IMCD cells, the specific activity of sorbitol dehydrogenase was relatively increased in a preparation of enriched interstitial cells. This distribution was not dependent on the various diuretic conditions. These results indicate that enzymes of synthesis and of degradation of sorbitol are osmotically regulated in vivo. Therefore, the enzymatic activities of sorbitol synthesis appear to be primarily located in epithelial cells, whereas enzymatic activities of sorbitol degradation seem to be localized in interstitial cells of the renal inner medulla.

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The role of SORBITOL DEHYDROGENASE in Arabidopsis thaliana

Functional Plant Biology ◽

10.1071/fp12008 ◽

2012 ◽

Vol 39 (6) ◽

pp. 462 ◽

Cited By ~ 18

Author(s):

Marta Nosarzewski ◽

A. Bruce Downie ◽

Benhong Wu ◽

Douglas D. Archbold

Keyword(s):

Arabidopsis Thaliana ◽

Drought Stress ◽

Sorbitol Dehydrogenase ◽

Primary Role ◽

Dependent Manner ◽

Plant Leaves ◽

Wild Type ◽

Concentration Dependent Manner ◽

Knockout Mutants

SORBITOL DEHYDROGENASE (SDH, EC 1.1.1.14) catalyses the interconversion of polyols and ketoses (e.g. sorbitol ↔ fructose). Using two independent Arabidopsis thaliana (L.) Heynh. sdh knockout mutants, we show that SDH (At5g51970) plays a primary role in sorbitol metabolism as well as an unexpected role in ribitol metabolism. Sorbitol content increased in both wild-type (WT) and mutant plant leaves during drought stress, but mutants showed a dramatically different phenotype, dying even if rewatered. The lack of functional SDH in mutant plants was accompanied by accumulation of foliar sorbitol and at least 10-fold more ribitol, neither of which decreased in mutant plants after rewatering. In addition, mutant plants were uniquely sensitive to ribitol in a concentration-dependent manner, which either prevented them from completing seed germination or inhibited seedling development, effects not observed with other polyols or with ribitol-treated WT plants. Ribitol catabolism may occur solely through SDH in A. thaliana, though at only 30% the rate of that for sorbitol. The results indicate a role for SDH in metabolism of sorbitol to fructose and in ribitol conversion to ribulose in A. thaliana during recovery from drought stress.

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The metabolism of 3-deoxy-3-fluoro-D-glucose by Locusta migratoria and Schistocerca gregaria

Canadian Journal of Biochemistry ◽

10.1139/o77-051 ◽

1977 ◽

Vol 55 (4) ◽

pp. 369-375 ◽

Cited By ~ 12

Author(s):

A. Romaschin ◽

N. F. Taylor ◽

D. A. Smith ◽

D. Lopes

Keyword(s):

Chromatographic Analysis ◽

Schistocerca Gregaria ◽

Fat Body ◽

Locusta Migratoria ◽

Competitive Inhibitor ◽

Sorbitol Dehydrogenase ◽

Kinetic Rate ◽

Temperature Programmed ◽

Isothermal Gas ◽

Sorbitol Metabolism

3-Deoxy-3-fluoro-D-glucose (3FG) administered by injection is toxic to adult Locusta migratoria or Schistocerca gregaria (LD50, 4.8 mg/g). Temperature-programmed and isothermal gas chromatographic analysis of poisoned locust haemolymph reveals the presence of a fluorinated metabolite identified as 3-deoxy-3-fluoro-D-glucitol (3FGL). The enzymes responsible for the accumulation of this metabolite are located in the fat body of the insect and partially purified as aldose reductase (alditol: NADP+ 1-oxidoreductase, EC 1.1.1.21) and sorbitol dehydrogenase (L-iditol: NAD+ 5-oxidoreductase, EC 1.1.1.14). 3FGL is shown to be both a competitive inhibitor of the NAD-linked sorbitol dehydrogenase with Ki 8.2 × 10−2 M as well as a substrate with Km 0.5 M. A kinetic rate equation is derived and verified to account for the kinetic duality of 3FGL. These results partially explain the toxic effects of 3FG and are consistent with, the presence of a hitherto undetected sorbitol metabolism in locusts.

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Polyol specificity of recombinant Arabidopsis thaliana sorbitol dehydrogenase studied by enzyme kinetics and in silico modeling

Frontiers in Plant Science ◽

10.3389/fpls.2015.00091 ◽

2015 ◽

Vol 6 ◽

Cited By ~ 3

Author(s):

M. Francisca Aguayo ◽

Juan Carlos CÃ¡ceres ◽

MatÃas Fuentealba ◽

Rodrigo MuÃ±oz ◽

Claudia Stange ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Enzyme Kinetics ◽

In Silico ◽

Sorbitol Dehydrogenase ◽

In Silico Modeling

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Patterns of Sorbitol Metabolism and Availability during Apple Fruit Set

HortScience ◽

10.21273/hortsci.39.4.887b ◽

2004 ◽

Vol 39 (4) ◽

pp. 887B-887

Author(s):

Douglas D. Archbold* ◽

Marta Nosarszewski

Keyword(s):

Specific Antibody ◽

Fruit Set ◽

Sucrose Concentration ◽

Apple Fruit ◽

Fruit Growth ◽

Sorbitol Dehydrogenase ◽

Prior Work ◽

Fruit Drop ◽

June Drop ◽

Sorbitol Metabolism

Acquiring sufficient carbohydrate is essential for successful apple fruit set. Sorbitol may be the dominant carbohydrate imported by growing fruit, and the rate of sorbitol accumulation may be a function of NAD-dependent sorbitol dehydrogenase (SDH; EC 1.1.1.14) activity. Prior work indicated that SDH activity from whole fruit (seeds plus cortex) increased for 2 or 3 weeks after initiation of fruit growth and then declined through 5 weeks. Using SDH activity assays, an SDH-specific antibody, and SDH-specific probes in Northern analyses, it is evident that SDH is expressed and is active in both apple seed and cortex tissue during the first few weeks of fruit growth. On a per unit protein basis, SDH activity in seeds increased by the pattern described above while that in fruit was generally lower and constant. During this same period of time, the sorbitol content of the expressed sap of apple shoots was analyzed. The sorbitol concentration was 50- to 100-fold higher than the sucrose concentration. The concentrations of both carbohydrates changed in parallel to the change in SDH activity of whole fruit and seeds. The lowest SDH activity and sap sorbitol levels preceded and/or coincided with the beginning of the natural fruit drop (or June drop) period.

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SORBITOL METABOLISM IN BACTERIA PATHOGENIC TO THE ROSACEAE FAMILY

HortScience ◽

10.21273/hortsci.27.6.630g ◽

1992 ◽

Vol 27 (6) ◽

pp. 630g-630

Author(s):

Dwight S. Fujii ◽

Abhaya M. Dandekar

Keyword(s):

Cellulose Acetate ◽

Sorbitol Dehydrogenase ◽

Sugar Alcohol ◽

Enzymatic Analysis ◽

Mannitol Dehydrogenase ◽

Cellulose Acetate Electrophoresis ◽

Polyol Dehydrogenase ◽

Michaelis Constants ◽

Rosaceae Family ◽

Sorbitol Metabolism

Many tree crops belonging to the Rosaceae family translocate and metabolize sorbitol. We have determined that some species of bacteria belonging to the genus Agrobacterium, Pseudomonas, and Erwinia pathogenic to the Rosaceae demonstrate the ability to metabolize sorbitol while those that were isolated from other hosts could not utilize sorbitol. Employing cellulose acetate electrophoresis (CAE) we have been able to demonstrate the presence of isoenzymes of sorbitol dehydrogenase (SDH) that correlate with the ability to metabolize sorbitol in these organisms. In order to study the properties of SDH in these organisms we carried out a detailed enzymatic analysis of the enzyme from A. tumefaciens. We found that the enzyme displayed activity when mannitol or xylitol were used as substrates, in addition to sorbitol. Michaelis constants (Km) were 32.8 mM, 0.19 mM, and 38.2 mM for sorbitol, mannitol, and xylitol respectively. To further distinguish the reactions with the different substrates the enzymatic extracts were further characterized on CAE using different substrates to visualize patterns of isoenzymes for a particular sugar alcohol. These analyses revealed the presence of unique isoenzymes for SDH. In addition we observed the presence of mannitol dehydrogenase (MDH) representing in most species a non-specific polyol dehydrogenase.

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High Temperature Alters Sorbitol Metabolism in Pyrus pyrifolia Leaves and Fruit Flesh during Late Stages of Fruit Enlargement

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.138.6.443 ◽

2013 ◽

Vol 138 (6) ◽

pp. 443-451 ◽

Cited By ~ 13

Author(s):

Dongfeng Liu ◽

Junbei Ni ◽

Ruiyuan Wu ◽

Yuanwen Teng

Keyword(s):

High Temperature ◽

High Temperatures ◽

Fruit Quality ◽

Temperature Treatment ◽

Sorbitol Dehydrogenase ◽

High Temperature Treatment ◽

Pyrus Pyrifolia ◽

Mature Leaves ◽

Fruit Flesh ◽

Sorbitol Metabolism

Sorbitol is the main photosynthetic product and primary translocated carbohydrate in the Rosaceae and plays fundamental roles in plant growth, fruit quality, and osmotic stress adaptation. To investigate the effect of frequent high temperature during advanced fruit development on fruit quality of chinese sand pear [Pyrus pyrifolia (Burm. f.) Nakai], we analyzed sorbitol metabolism in mature leaves and fruit flesh of potted ‘Wonhwang’ pear trees. In mature leaves, sorbitol synthesis catalyzed by NADP+-dependent sorbitol-6-phosphate dehydrogenase (S6PDH) was repressed, while sorbitol utilization mainly catalyzed by NAD+-dependent sorbitol dehydrogenase (NAD+-SDH) and NADP+-dependent sorbitol dehydrogenase (NADP+-SDH) was higher than that before high-temperature treatment, which resulted in decreased sorbitol accumulation. In contrast, sucrose accumulation in mature leaves was significantly enhanced in response to high temperatures. In fruit flesh, accumulation of sorbitol and sucrose was increased at the time of harvest under high temperatures. Among sorbitol metabolic enzymes, only NAD+-SDH was sensitive to high temperature in fruit flesh, and significant decrease of NAD+-SDH activity indicated that the fruit sorbitol-uptake capacity was undermined under high temperatures. Transcription analysis revealed tissue-specific responses of NAD+-SDH genes (PpSDH1, PpSDH2, and PpSDH3) to high-temperature treatment. The NAD+-SDH activity and regulation of PpSDH1 and PpSDH3 were positively correlated in mature leaves. However, the downregulation of PpSDH1 and PpSDH2 was consistent with decreased enzyme activity in the fruit flesh. With regard to sorbitol transport, two sorbitol transporter genes (PpSOT1 and PpSOT2) were isolated, and downregulation of PpSOT2 expression in mature leaves indicated that the sorbitol-loading capability decreased under high-temperature conditions because of the limited sorbitol supply. These findings suggested that sorbitol metabolism responded differently in mature leaves and fruit flesh under high temperature, and that these dissimilar responses influenced fruit quality and may play important roles in adaptation to high temperatures.

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