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Chang-su Park - One of the best experts on this subject based on the ideXlab platform.
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substrate specificity of a recombinant d lyxose isomerase from providencia stuartii for monosaccharides
Journal of Bioscience and Bioengineering, 2010Co-Authors: Hyunjung Kwon, Soo Jin Yeom, Chang-su Park, Deok-kun OhAbstract:The specific activity and catalytic efficiency (k(cat)/K(m)) of the recombinant putative protein from Providencia stuartii was the highest for D-lyxose among the Aldose substrates, indicating that it is a D-lyxose isomerase. Gel filtration analysis suggested that the native enzyme is a dimer with a molecular mass of 44 kDa. The maximal activity for D-lyxose isomerization was observed at pH 7.5 and 45 degrees C in the presence of 1 mM Mn(2+). The enzyme exhibited high isomerization activity for Aldose substrates with the C2 and C3 hydroxyl groups in the left-hand configuration, such as D-lyxose, D-mannose, L-ribose, D-talose, and L-allose (listed in decreasing order of activity). The enzyme exhibited the highest activity for D-xylulose among all pentoses and hexoses. Thus, D-lyxose was produced at 288 g/l from 500 g/l D-xylulose by D-lyxose isomerase at pH 7.5 and 45 degrees C for 2 h, with a conversion yield of 58% and a volumetric productivity of 144 g l(-1) h(-1). The observed k(cat)/K(m) (920 mM(-1) s(-1)) of P. stuartiid-lyxose isomerase for D-xylulose is higher than any of the k(cat)/K(m) values previously reported for sugar and sugar phosphate isomerases with monosaccharide substrates. These results suggest that the enzyme will be useful as an industrial producer of D-lyxose.
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Substrate specificity of ribose-5-phosphate isomerases from Clostridium difficile and Thermotoga maritima.
Biotechnology Letters, 2010Co-Authors: Soo Jin Yeom, Chang-su Park, Deok-kun OhAbstract:The activity of ribose-5-phosphate isomerases (RpiB) from Clostridium difficile for d-ribose isomerization was optimal at pH 7.5 and 40°C, while that from Thermotoga maritima for l-talose isomerization was optimal at pH 8.0 and 70°C. C. difficile RpiB exhibited activity only with Aldose substrates possessing hydroxyl groups oriented in the right-handed configuration (Fischer projections) at the C2 and C3 positions, such as d-ribose, d-allose, l-talose, l-lyxose, d-gulose, and l-mannose. In contrast, T. maritima RpiB displayed activity only with Aldose substrates possessing hydroxyl groups configured the same direction at the C2, C3, and C4 positions, such as the d- and l-forms of ribose, talose, and allose.
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substrate specificity of a mannose 6 phosphate isomerase from bacillus subtilis and its application in the production of l ribose
Applied and Environmental Microbiology, 2009Co-Authors: Soo Jin Yeom, Namhee Kim, Chang-su ParkAbstract:The uncharacterized gene previously proposed as a mannose-6-phosphate isomerase from Bacillus subtilis was cloned and expressed in Escherichia coli. The maximal activity of the recombinant enzyme was observed at pH 7.5 and 40°C in the presence of 0.5 mM Co2+. The isomerization activity was specific for Aldose substrates possessing hydroxyl groups oriented in the same direction at the C-2 and C-3 positions, such as the d and l forms of ribose, lyxose, talose, mannose, and allose. The enzyme exhibited the highest activity for l-ribulose among all pentoses and hexoses. Thus, l-ribose, as a potential starting material for many l-nucleoside-based pharmaceutical compounds, was produced at 213 g/liter from 300-g/liter l-ribulose by mannose-6-phosphate isomerase at 40°C for 3 h, with a conversion yield of 71% and a volumetric productivity of 71 g liter−1 h−1.
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characterization of a mannose 6 phosphate isomerase from geobacillus thermodenitrificans that converts monosaccharides
Biotechnology Letters, 2009Co-Authors: Namhee Kim, Ran-young Yoon, Hyunjung Kwon, Chang-su ParkAbstract:A recombinant mannose-6-phosphate isomerase from Geobacillus thermodenitrificans (GTMpi) isomerizes Aldose substrates possessing hydroxyl groups oriented in the same direction at the C2 and C3 positions such as the d- and l-forms of ribose, lyxose, talose, mannose, and allose. The activity of GTMpi for d-lyxose isomerization was optimal at pH 7.0, 70°C and 1 mM Co2+. Under these conditions, the kcat and Km values were 74,300 s−1 and 390 mM for d-lyxose and 28,800 s−1 and 470 mM for l-ribose, respectively. The half-lives of the enzyme at 60, 65, and 70°C were 388, 73, and 27 h, respectively. GTMpi catalyzed the conversion of d-lyxose to d-xylulose with a 38% conversion yield after 3 h, and converted l-ribose to l-ribulose with a 29% conversion yield.
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substrate specificity of a glucose 6 phosphate isomerase from pyrococcus furiosus for monosaccharides
Applied Microbiology and Biotechnology, 2009Co-Authors: Ran-young Yoon, Soo Jin Yeom, Chang-su ParkAbstract:We purified recombinant glucose-6-phosphate isomerase from Pyrococcus furiosus using heat treatment and Hi-Trap anion-exchange chromatography with a final specific activity of 0.39 U mg−1. The activity of the glucose-6-phosphate isomerase for l-talose isomerization was optimal at pH 7.0, 95°C, and 1.5 mM Co2+. The half-lives of the enzyme at 65°C, 75°C, 85°C, and 95°C were 170, 41, 19, and 7.9 h, respectively. Glucose-6-phosphate isomerase catalyzed the interconversion between two different Aldoses and ketose for all pentoses and hexoses via two isomerization reactions. This enzyme has a unique activity order as follows: Aldose substrates with hydroxyl groups oriented in the same direction at C2, C3, and C4 > C2 and C4 > C2 and C3 > C3 and C4. l-Talose and d-ribulose exhibited the most preferred substrates among the Aldoses and ketoses, respectively. l-Talose was converted to l-tagatose and l-galactose by glucose-6-phosphate isomerase with 80% and 5% conversion yields after about 420 min, respectively, whereas d-ribulose was converted to d-ribose and d-arabinose with 53% and 8% conversion yields after about 240 min, respectively.
Satish K Srivastava - One of the best experts on this subject based on the ideXlab platform.
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requirement of Aldose reductase for the hyperglycemic activation of protein kinase c and formation of diacylglycerol in vascular smooth muscle cells
Diabetes, 2005Co-Authors: Kavuluri Venkata Ramana, Brian M. Friedrich, Aruni Bhatnagar, Matthew B West, Ravinder Tammali, Satish K SrivastavaAbstract:Activation of protein kinase C (PKC) has been linked to the development of secondary diabetes complications. However, the underlying molecular mechanisms remain unclear. We examined the contribution of Aldose reductase, which catalyzes the first, and the rate-limiting, step of the polyol pathway of glucose metabolism, to PKC activation in vascular smooth muscle cells (VSMCs) isolated from rat aorta and exposed to high glucose in culture. Exposure of VSMCs to high glucose (25 mmol/l), but not iso-osmotic mannitol, led to an increase in total membrane-associated PKC activity, which was prevented by the Aldose reductase inhibitors tolrestat or sorbinil or by the ablation of Aldose reductase by small interfering RNA (siRNA). The VSMCs were found to express low levels of sorbitol dehydrogenase, and treatment with the sorbitol dehydrogenase inhibitor CP-166572 did not prevent high-glucose-induced PKC activation. Stimulation with high glucose caused membrane translocation of conventional (α, β1, β2, and γ) and novel (δ and e) isoforms of PKC. Inhibition of Aldose reductase prevented membrane translocation of PKC-β2 and -δ and delayed the activation of PKC-β1 and -e, whereas membrane translocation of PKC-α and -γ was not affected. Treatment with tolrestat prevented phosphorylation of PKC-β2 and -δ. High glucose increased the formation of diacylglycerol (DAG) and enhanced phosphorylation of phospholipase C-γ1 (PLC-γ1). Inhibition of Aldose reductase prevented high glucose-induced DAG formation and phosphorylation of PLC-γ1 and PLC-β2 and -δ. Inhibition of phospholipid hydrolysis by D609, but not by the synthetic alkyl-1-lysophospholipid 1-O-octadecyl-2-O-methyl- rac -glycerophosphocholine, or edelfosine, prevented DAG formation. Treatment with sorbinil decreased the levels of reactive oxygen species in high-glucose-stimulated VSMCs. Hence, inhibition of Aldose reductase, independent of sorbitol dehydrogenase, appears to be effective in diminishing oxidative stress and hyperglycemic changes in signaling events upstream to the activation of multiple PKC isoforms and PLC-γ1 and may represent a useful approach for preventing the development of secondary vascular complications of diabetes.
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Activation of Nulcear Factor-κB by Hyperglycemia in Vascular Smooth Muscle Cells Is Regulated by Aldose Reductase
Diabetes, 2004Co-Authors: Kavuluri Venkata Ramana, Brian M. Friedrich, Aruni Bhatnagar, Sanjay Srivastava, Satish K SrivastavaAbstract:Activation of the polyol pathway has been linked to the development of secondary diabetic complications. However, the underlying molecular mechanisms remain unclear. To probe the contribution of this pathway, we examined whether inhibition of Aldose reductase, which catalyzes the first step of the pathway, affects hyperglycemia-induced activation of the inflammatory transcription factor nuclear factor (NF)-κB. Treatment of vascular smooth muscle cells with the Aldose reductase inhibitors tolrestat and sorbinil prevented high-glucose–induced protein kinase C (PKC) activation, nuclear translocation of NF-κB, phosphorylation of IKK, and the increase in the expression of intracellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, and Aldose reductase. High-glucose–induced NF-κB activation was also prevented by the PKC inhibitors chelerythrine and calphostin C. Ablation of Aldose reductase by small interference RNA (siRNA) prevented high-glucose–induced NF-κB and AP-1 activation but did not affect the activity of SP-1 or OCT-1. Stimulation with iso-osmotic mannitol activated NF-κB and increased the expression of Aldose reductase but not ICAM-1 and VCAM-1. Treatment with Aldose reductase inhibitors or Aldose reductase siRNA did not affect mannitol-induced NF-κB or AP-1 activation. Administration of tolrestat (15 mg · kg −1 · day −1 ) decreased the abundance of activated NF-κB in balloon-injured carotid arteries of diabetic rats. Collectively, these results suggest that inhibition of Aldose reductase, which prevents PKC-dependent nonosmotic NF-κB activation, may be a useful approach for treating vascular inflammation caused by diabetes.
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structural and kinetic determinants of aldehyde reduction by Aldose reductase
Biochemistry, 1999Co-Authors: Sanjay K Srivastava, Mark J Petrash, Satish K Srivastava, Stanley J Watowich, Aruni BhatnagarAbstract:Aldose reductase (AR) is a member of the aldo-keto reductase superfamily. Due to its ability to catalyze the formation of sorbitol from glucose during hyperglycemic and hypertonic stress, the aldos...
Ying Gai - One of the best experts on this subject based on the ideXlab platform.
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Optimized GC-MS Method To Simultaneously Quantify Acetylated Aldose, Ketose, and Alditol for Plant Tissues Based on Derivatization in a Methyl Sulfoxide/1-Methylimidazole System
2016Co-Authors: Shichang Liu, Yupeng Tan, Nan Chao, Xiaoming Tian, William A. Powell, Xiangning Jiang, Ying GaiAbstract:The isomers of monosaccharide always produce multiple chromatographic peaks as volatile derivatives during gas chromatography, which may result in the overlapping of different sugar peaks. Whereas reduction and oximation of sugar carbonyl groups for GC analysis do eliminate many isomer derivatives, the approaches create new problems. One ketose can yield two peaks by oximation, and different Aldoses and ketoses can yield the same alditol upon reduction, leading to the inability to detect some important monosaccharides. This paper reports an optimal method that yields a single peak per sugar by acetylation directly. By using a methyl sulfoxide (Me2SO)/1-methylimidazole (1-MeIm) system, the carbohydrates in acetic anhydride (Ac2O) esterification reactions were solubilized, and the oxidation that normally occurs was inhibited. The results demonstrate that acetylated derivatives of 23 saccharides had unique peaks, which indicates Aldose, ketose, and alditol can be determined simultaneously by GC-MS
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Optimized GC-MS method to simultaneously quantify acetylated Aldose, ketose, and alditol for plant tissues based on derivatization in a methyl sulfoxide/1-methylimidazole system.
Journal of Agricultural and Food Chemistry, 2013Co-Authors: Shichang Liu, Yupeng Tan, Nan Chao, Xiaoming Tian, William A. Powell, Xiangning Jiang, Ying GaiAbstract:The isomers of monosaccharide always produce multiple chromatographic peaks as volatile derivatives during gas chromatography, which may result in the overlapping of different sugar peaks. Whereas reduction and oximation of sugar carbonyl groups for GC analysis do eliminate many isomer derivatives, the approaches create new problems. One ketose can yield two peaks by oximation, and different Aldoses and ketoses can yield the same alditol upon reduction, leading to the inability to detect some important monosaccharides. This paper reports an optimal method that yields a single peak per sugar by acetylation directly. By using a methyl sulfoxide (Me2SO)/1-methylimidazole (1-MeIm) system, the carbohydrates in acetic anhydride (Ac2O) esterification reactions were solubilized, and the oxidation that normally occurs was inhibited. The results demonstrate that acetylated derivatives of 23 saccharides had unique peaks, which indicates Aldose, ketose, and alditol can be determined simultaneously by GC-MS.
Soo Jin Yeom - One of the best experts on this subject based on the ideXlab platform.
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substrate specificity of a recombinant d lyxose isomerase from providencia stuartii for monosaccharides
Journal of Bioscience and Bioengineering, 2010Co-Authors: Hyunjung Kwon, Soo Jin Yeom, Chang-su Park, Deok-kun OhAbstract:The specific activity and catalytic efficiency (k(cat)/K(m)) of the recombinant putative protein from Providencia stuartii was the highest for D-lyxose among the Aldose substrates, indicating that it is a D-lyxose isomerase. Gel filtration analysis suggested that the native enzyme is a dimer with a molecular mass of 44 kDa. The maximal activity for D-lyxose isomerization was observed at pH 7.5 and 45 degrees C in the presence of 1 mM Mn(2+). The enzyme exhibited high isomerization activity for Aldose substrates with the C2 and C3 hydroxyl groups in the left-hand configuration, such as D-lyxose, D-mannose, L-ribose, D-talose, and L-allose (listed in decreasing order of activity). The enzyme exhibited the highest activity for D-xylulose among all pentoses and hexoses. Thus, D-lyxose was produced at 288 g/l from 500 g/l D-xylulose by D-lyxose isomerase at pH 7.5 and 45 degrees C for 2 h, with a conversion yield of 58% and a volumetric productivity of 144 g l(-1) h(-1). The observed k(cat)/K(m) (920 mM(-1) s(-1)) of P. stuartiid-lyxose isomerase for D-xylulose is higher than any of the k(cat)/K(m) values previously reported for sugar and sugar phosphate isomerases with monosaccharide substrates. These results suggest that the enzyme will be useful as an industrial producer of D-lyxose.
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Substrate specificity of ribose-5-phosphate isomerases from Clostridium difficile and Thermotoga maritima.
Biotechnology Letters, 2010Co-Authors: Soo Jin Yeom, Chang-su Park, Deok-kun OhAbstract:The activity of ribose-5-phosphate isomerases (RpiB) from Clostridium difficile for d-ribose isomerization was optimal at pH 7.5 and 40°C, while that from Thermotoga maritima for l-talose isomerization was optimal at pH 8.0 and 70°C. C. difficile RpiB exhibited activity only with Aldose substrates possessing hydroxyl groups oriented in the right-handed configuration (Fischer projections) at the C2 and C3 positions, such as d-ribose, d-allose, l-talose, l-lyxose, d-gulose, and l-mannose. In contrast, T. maritima RpiB displayed activity only with Aldose substrates possessing hydroxyl groups configured the same direction at the C2, C3, and C4 positions, such as the d- and l-forms of ribose, talose, and allose.
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substrate specificity of a mannose 6 phosphate isomerase from bacillus subtilis and its application in the production of l ribose
Applied and Environmental Microbiology, 2009Co-Authors: Soo Jin Yeom, Namhee Kim, Chang-su ParkAbstract:The uncharacterized gene previously proposed as a mannose-6-phosphate isomerase from Bacillus subtilis was cloned and expressed in Escherichia coli. The maximal activity of the recombinant enzyme was observed at pH 7.5 and 40°C in the presence of 0.5 mM Co2+. The isomerization activity was specific for Aldose substrates possessing hydroxyl groups oriented in the same direction at the C-2 and C-3 positions, such as the d and l forms of ribose, lyxose, talose, mannose, and allose. The enzyme exhibited the highest activity for l-ribulose among all pentoses and hexoses. Thus, l-ribose, as a potential starting material for many l-nucleoside-based pharmaceutical compounds, was produced at 213 g/liter from 300-g/liter l-ribulose by mannose-6-phosphate isomerase at 40°C for 3 h, with a conversion yield of 71% and a volumetric productivity of 71 g liter−1 h−1.
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substrate specificity of a glucose 6 phosphate isomerase from pyrococcus furiosus for monosaccharides
Applied Microbiology and Biotechnology, 2009Co-Authors: Ran-young Yoon, Soo Jin Yeom, Chang-su ParkAbstract:We purified recombinant glucose-6-phosphate isomerase from Pyrococcus furiosus using heat treatment and Hi-Trap anion-exchange chromatography with a final specific activity of 0.39 U mg−1. The activity of the glucose-6-phosphate isomerase for l-talose isomerization was optimal at pH 7.0, 95°C, and 1.5 mM Co2+. The half-lives of the enzyme at 65°C, 75°C, 85°C, and 95°C were 170, 41, 19, and 7.9 h, respectively. Glucose-6-phosphate isomerase catalyzed the interconversion between two different Aldoses and ketose for all pentoses and hexoses via two isomerization reactions. This enzyme has a unique activity order as follows: Aldose substrates with hydroxyl groups oriented in the same direction at C2, C3, and C4 > C2 and C4 > C2 and C3 > C3 and C4. l-Talose and d-ribulose exhibited the most preferred substrates among the Aldoses and ketoses, respectively. l-Talose was converted to l-tagatose and l-galactose by glucose-6-phosphate isomerase with 80% and 5% conversion yields after about 420 min, respectively, whereas d-ribulose was converted to d-ribose and d-arabinose with 53% and 8% conversion yields after about 240 min, respectively.
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Novel substrates of a ribose-5-phosphate isomerase from Clostridium thermocellum.
Journal of Biotechnology, 2008Co-Authors: Ran-young Yoon, Soo Jin Yeom, Deok-kun OhAbstract:A substrate specificity study of the recombinant D-ribose-5-phosphate isomerase (RpiB) from Clostridium thermocellum was performed. Among all aldopentoses and aldohexoses, the RpiB enzyme displayed activity with L-talose, D-ribose, D-allose, L-allose, L-ribose, and D-talose in decreasing order. The products released were L-tagatose, D-ribulose, D-psicose, L-psicose, L-ribulose, and D-tagatose, respectively. The enzyme showed specificity for Aldose substrates possessing hydroxyl groups oriented in the same direction at the C2, C3, and C4 positions. Molecular modeling of the enzyme suggests that the novel substrate specificity may be explained by substrate interactions with residues Tyr42, His98, and His9, which interact with the hydroxyl groups of C2, C3, and C4, respectively, oriented in the same direction. L-Talose and D-ribulose exhibited the highest activity among the Aldoses and ketoses, respectively. Ribose 5-phosphate isomerase catalyzed the conversion of L-talose to L-tagatose with an 89% conversion yield after approximately 90 min, while D-ribulose was converted to D-ribose with a 38% conversion yield.
Aruni Bhatnagar - One of the best experts on this subject based on the ideXlab platform.
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requirement of Aldose reductase for the hyperglycemic activation of protein kinase c and formation of diacylglycerol in vascular smooth muscle cells
Diabetes, 2005Co-Authors: Kavuluri Venkata Ramana, Brian M. Friedrich, Aruni Bhatnagar, Matthew B West, Ravinder Tammali, Satish K SrivastavaAbstract:Activation of protein kinase C (PKC) has been linked to the development of secondary diabetes complications. However, the underlying molecular mechanisms remain unclear. We examined the contribution of Aldose reductase, which catalyzes the first, and the rate-limiting, step of the polyol pathway of glucose metabolism, to PKC activation in vascular smooth muscle cells (VSMCs) isolated from rat aorta and exposed to high glucose in culture. Exposure of VSMCs to high glucose (25 mmol/l), but not iso-osmotic mannitol, led to an increase in total membrane-associated PKC activity, which was prevented by the Aldose reductase inhibitors tolrestat or sorbinil or by the ablation of Aldose reductase by small interfering RNA (siRNA). The VSMCs were found to express low levels of sorbitol dehydrogenase, and treatment with the sorbitol dehydrogenase inhibitor CP-166572 did not prevent high-glucose-induced PKC activation. Stimulation with high glucose caused membrane translocation of conventional (α, β1, β2, and γ) and novel (δ and e) isoforms of PKC. Inhibition of Aldose reductase prevented membrane translocation of PKC-β2 and -δ and delayed the activation of PKC-β1 and -e, whereas membrane translocation of PKC-α and -γ was not affected. Treatment with tolrestat prevented phosphorylation of PKC-β2 and -δ. High glucose increased the formation of diacylglycerol (DAG) and enhanced phosphorylation of phospholipase C-γ1 (PLC-γ1). Inhibition of Aldose reductase prevented high glucose-induced DAG formation and phosphorylation of PLC-γ1 and PLC-β2 and -δ. Inhibition of phospholipid hydrolysis by D609, but not by the synthetic alkyl-1-lysophospholipid 1-O-octadecyl-2-O-methyl- rac -glycerophosphocholine, or edelfosine, prevented DAG formation. Treatment with sorbinil decreased the levels of reactive oxygen species in high-glucose-stimulated VSMCs. Hence, inhibition of Aldose reductase, independent of sorbitol dehydrogenase, appears to be effective in diminishing oxidative stress and hyperglycemic changes in signaling events upstream to the activation of multiple PKC isoforms and PLC-γ1 and may represent a useful approach for preventing the development of secondary vascular complications of diabetes.
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Activation of Nulcear Factor-κB by Hyperglycemia in Vascular Smooth Muscle Cells Is Regulated by Aldose Reductase
Diabetes, 2004Co-Authors: Kavuluri Venkata Ramana, Brian M. Friedrich, Aruni Bhatnagar, Sanjay Srivastava, Satish K SrivastavaAbstract:Activation of the polyol pathway has been linked to the development of secondary diabetic complications. However, the underlying molecular mechanisms remain unclear. To probe the contribution of this pathway, we examined whether inhibition of Aldose reductase, which catalyzes the first step of the pathway, affects hyperglycemia-induced activation of the inflammatory transcription factor nuclear factor (NF)-κB. Treatment of vascular smooth muscle cells with the Aldose reductase inhibitors tolrestat and sorbinil prevented high-glucose–induced protein kinase C (PKC) activation, nuclear translocation of NF-κB, phosphorylation of IKK, and the increase in the expression of intracellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, and Aldose reductase. High-glucose–induced NF-κB activation was also prevented by the PKC inhibitors chelerythrine and calphostin C. Ablation of Aldose reductase by small interference RNA (siRNA) prevented high-glucose–induced NF-κB and AP-1 activation but did not affect the activity of SP-1 or OCT-1. Stimulation with iso-osmotic mannitol activated NF-κB and increased the expression of Aldose reductase but not ICAM-1 and VCAM-1. Treatment with Aldose reductase inhibitors or Aldose reductase siRNA did not affect mannitol-induced NF-κB or AP-1 activation. Administration of tolrestat (15 mg · kg −1 · day −1 ) decreased the abundance of activated NF-κB in balloon-injured carotid arteries of diabetic rats. Collectively, these results suggest that inhibition of Aldose reductase, which prevents PKC-dependent nonosmotic NF-κB activation, may be a useful approach for treating vascular inflammation caused by diabetes.
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structural and kinetic determinants of aldehyde reduction by Aldose reductase
Biochemistry, 1999Co-Authors: Sanjay K Srivastava, Mark J Petrash, Satish K Srivastava, Stanley J Watowich, Aruni BhatnagarAbstract:Aldose reductase (AR) is a member of the aldo-keto reductase superfamily. Due to its ability to catalyze the formation of sorbitol from glucose during hyperglycemic and hypertonic stress, the aldos...