Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.4 (SOR)
 720 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We treated leaves of winter wheat (Triticum aestivum L.) with cold, paraquat, or 3-amino-1,2,4-triazole and compared the responses. We assayed the activities of glucose-6-phosphate dehydrogenase, catalase, dehydroascorbate reductase and ascorbate free radical reductase and levels of hydrogen peroxide, glucose-6-phosphate, fructose-6-phosphate, ascorbate, dehydroascorbate, reduced and oxidized glutathione. With any of the three treatments, contents of cellular peroxides and hexose phosphates were raised. The content of ascorbate was lowered markedly by paraquat treatment, which produces active oxygen species, whereas such a decrease did not occur in other two treatments. When the plants were treated with 3-amino-1,2,4-triazole, which is a specific inhibitor of catalase, the content of oxidized glutathione increased severalfold. The glucose-6-phosphate dehydrogenase activity increased with all three treatments, but it decreased after glyphosate treatment, which does not stimulate the formation of peroxides. The activities of catalase and dehydroascorbate reductase were increased by the treatment of cold and paraquat, while 3-amino-1,2,4-triazole did not affect the dehydroascorbate reductase activity. The activity of ascorbate free radical reductase increased after treatment by paraquat only.
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PMID:Metabolic response to treatment with cold, paraquat, or 3-amino-1,2,4-triazole in leaves of winter wheat. 136 90

The bacterium Sinorhizobium morelense S-30.7.5 was isolated by a microbial screening using the sugar 1,5-anhydro-D-fructose (AF) as the sole carbon source. This strain metabolized AF by a novel pathway involving its reduction to 1,5-anhydro-D-mannitol (AM) and the further conversion of AM to D-mannose by C-1 oxygenation. Growth studies showed that the AF metabolizing capability is not confined to S. morelense S-30.7.5 but is a more common feature among the Rhizobiaceae. The AF reducing enzyme was purified and characterized as a new NADPH-dependent monomeric reductase (AFR, EC 1.1.1.-) of 35.1 kDa. It catalyzed the stereoselective reduction of AF to AM and also the conversion of a number of 2-keto aldoses (osones) to the corresponding manno-configurated aldoses. In contrast, common aldoses and ketoses, as well as nonsugar aldehydes and ketones, were not reduced. A database search using the N-terminal AFR sequence retrieved a putative 35-kDa oxidoreductase encoded by the open reading frame Smc04400 localized on the chromosome of Sinorhizobium meliloti 1021. Based on sequence information for this locus, the afr gene was cloned from S. morelense S-30.7.5 and overexpressed in Escherichia coli. In addition to the oxidoreductase of S. meliloti 1021, AFR showed high sequence similarities to putative oxidoreductases of Mesorhizobium loti, Brucella suis, and B. melitensis but not to any oxidoreductase with known functions. AFR could be assigned to the GFO/IDH/MocA family on the basis of highly conserved common structural features. His6-tagged AFR was used to demonstrate the utility of this enzyme for AF analysis and synthesis of AM, as well as related derivatives.
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PMID:Catabolism of 1,5-anhydro-D-fructose in Sinorhizobium morelense S-30.7.5: discovery, characterization, and overexpression of a new 1,5-anhydro-D-fructose reductase and its application in sugar analysis and rare sugar synthesis. 1646 73

Ascorbic acid (L-AsA) is an important antioxidant in plants and humans. Vegetables are one of the main sources of ascorbic acid for humans. For instance, non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) is considered as one of the most important vegetables in south China. To elucidate the mechanism by which AsA accumulates, we systematically investigated the expression profiles of D-mannose/L-galactose pathway-related genes. We also investigated the recycling-related genes and AsA contents in different tissues of three non-heading Chinese cabbage cultivars, 'Suzhouqing', 'Wutacai' and 'Erqing' containing different amounts of AsA. Our results showed that six genes [D-mannose-6-phosphate isomerase 1 (PMI1), GDP-L-galactose phosphorylase 1 (GGP1), GGP2, GGP4, GDP-mannose-3', 5'-epimerase1 (GME1), and GME2] were expressed at high level and ascorbate oxidase (AAO) was expressed at low level. This expression pattern contributes, at least partially, to higher AsA accumulation in the leaves and petioles than in the roots. Eight genes (PMI1, GME, GGP, L-galactose-1-phosphate phosphatase, L-galactose dehydrogenase, L-galactono-1, 4-lactone dehydrogenase, monodehydroascorbate reductase 1, and glutathione reductase1) were also expressed at high level; AAO and ascorbate peroxidase (APX) were expressed at low level. This expression pattern may similarly contribute to higher AsA accumulation in 'Wutacai' and 'Suzhouqing' than in 'Erqing'. Therefore, the high expression levels of PMI, GME, and GGP and the low expression level of AAO contributed to the high AsA accumulation in non-heading Chinese cabbage.
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PMID:Comparison of ascorbic acid biosynthesis in different tissues of three non-heading Chinese cabbage cultivars. 2415 1