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Click here for the function of GRE3. Edit this page in WikiGenes - GRE3. Enhanced glycerol yields were observed in the high- XR-activity strains. Paper-9699330. In chemostat cultivation, part of the population lost the plasmid harboring the XR gene. Paper-12809572. Overexpression of GRE3 increases methylglyoxal tolerance in Saccharomyces cerevisiae. Paper-8897977. Xylose reductase and xylitol dehydrogenase convert xylose to its isomer xylulose. Paper-8938528. In recombinant strains from which the GRE3 gene was deleted, xylitol formation decreased twofold. Paper-10720553. However, the XOR activities of the two strains grown on xylose were similar under oxygen limitation. Paper-577623. Xylose utilisation: cloning and characterisation of the Xylose reductase from Candida tenuis. Paper-2117859. Oxygen limitation led to higher XOR activity in both experimental and control strains grown on xylose. Paper-577623. In addition, the GRE3 gene encoding aldose reductase was deleted to further minimise xylitol production. Paper-10788147. Site-directed mutagenesis of the cysteine residues in the Pichia stipitis xylose reductase. Paper-954345. Cloning and expression of Candida guilliermondii xylose reductase gene ( xyl1) in Pichia pastoris. Paper-1463951. At the higher dilution rate, control by some other factor such as xylose transport or XR activity increased. Paper-496406. Investigation of the role of a conserved glycine motif in the Saccharomyces cerevisiae xylose reductase. Paper-12064887. In order to express the xylose reductase in E. coli, the gene was placed under positive and negative control. Paper-2117859. In the ZWF1-disrupted background, the increase in XR activity fully restored the xylose consumption rate. Paper-9699330. Measurement of intracellular levels of XR, XDH, and XK activities confirmed the expected phenotypes. Paper-12783461. Yeasts can metabolize xylose by the action of two key enzymes: xylose reductase and xylitol dehydrogenase. Paper-12313358. The XYL1 encodes a polypeptide of 35,927 Da that constitutes a NADH/ NADPH-dependent xylose reductase ( XR). Paper-48715. Properties of the NAD(P)H-dependent xylose reductase from the xylose-fermenting yeast Pichia stipitis. Paper-5106026. The XR present in C. mogii extracts showed a superior Km value for xylose when compared with other yeast strains. Paper-12008516. This mutant has a deletion of the XYL1 gene encoding xylose reductase and is not able to grow in the xylose medium. Paper-10980450. Both the D-xylose reductase and the L-arabinose reductase activities exclusively used NADPH as co-factor. Paper-9333883. These are suggested to result from the observed reductase activity of the purified XR for dihydroxyacetone phosphate. Paper-9699330. Both EI and EII, which were purified by affinity chromatography, had NADPH-dependent xylose reductase activities. Paper-12810662. Increased xylose reductase activity in the xylose-fermenting yeast Pichia stipitis by overexpression of XYL1. Paper-577623. A NADPH/NADH-dependent xylose reductase gene was isolated from the xylose-assimilating yeast, Pichia stipitis. Paper-42428. The xyl1 gene encoding xylose reductase was cloned from Saccharomyces cerevisiae and expressed in Escherichia coli. Paper-8852991. Structural and functional properties of aldose xylose reductase from the D-xylose-metabolizing yeast Candida tenuis. Paper-8726537. Methanol induced the expression of the 36-kDa xylose reductase in both intracellular and secreted expression systems. Paper-1463951. The derived amino acid sequence of C. guilliermondii xylose reductase was 70.4% homologous to that of Pichia stipitis. Paper-1463951. In this work, the xylose reductase gene from Candida tenuis CBS 4435 was cloned and successfully expressed in E. coli. Paper-2117859. Xylose was the appropriate inducer for the production of xylose reductase that had two isoenzymes designated as EI and EII. Paper-12810662. Xylose reductase ( XR) is a key enzyme in D-xylose metabolism, catalyzing the reduction of D-xylose to xylitol. Paper-10068374. We used site-directed mutagenesis to study the role of this SDR-like Gly motif in the S. cerevisiae xylose reductase. Paper-12064887. Xylose transport, xylose reductase, and xylitol dehydrogenase activities are demonstrated in Saccharomyces cerevisiae. Paper-12800800. All strains with high activity of both XR and XDH had increased ethanol yields and significantly decreased xylitol yields. Paper-12378852. C. shehatae seems to contain only a single xylose reductase, but the enzyme has a dual coenzyme specificity for both NADPH and NADH. Paper-12928. Under all cultivation conditions, nicotinamide adenine dinucleotide (NADH) was the preferred cofactor for xylose reductase. Paper-8729162. The Pichia stipitis xylose reductase gene (XYL1) was inserted into an autonomous plasmid that P. stipitis maintains in multicopy. Paper-577623. Likewise, the yields of xylitol (0.19 g/g) and glycerol (0.02 g/g) were decreased 52% and 57% respectively in the XR mutant strain. Paper-12783461. Structure of xylose reductase bound to NAD+ and the basis for single and dual co-substrate specificity in family 2 aldo-keto reductases. Paper-9779084. The high xylitol production (20.0 g/L) and xylose reductase ( XR) activity (658.8 U/mg of protein) occurred at an aeration of 0.4 vvm. Paper-10726215. High activity of xylose reductase and xylitol dehydrogenase improves xylose fermentation by recombinant Saccharomyces cerevisiae. Paper-12378852. Strains which coexpressed chimerical subunits together with native XR and XDH monomers consumed less xylose and produced less xylitol. Paper-9021358. The stability of the recombinant strains after 15 days of continuous operation was evaluated by XR activity and plasmid retention analyses. Paper-12808791. This host strain has integrated xylose-metabolizing genes, including xylose reductase, xylitol dehydrogenase, and xylulose kinase. Paper-12562106. When the GRE3 gene was overexpressed in this strain, the xylose consumption and ethanol formation increased by 29% and 116%, respectively. Paper-10384548. Xylose reductase catalyzes the reduction of xylose to xylitol and is known to play a pivotal role in pentose metabolism in yeasts. Paper-954345. The K(m)s against xylose for EI and EII were 2.3 mM and 1.1 mM respectively, which were much lower than those of the xylose reductase from yeast. Paper-12810662. Xylitol production using recombinant Saccharomyces cerevisiae containing multiple xylose reductase genes at chromosomal delta-sequences. Paper-1776764. The identification of a xylose reductase (XR)-encoding gene (XYL1) from the xylose-assimilating yeast Kluyveromyces lactis (Kl) is described. Paper-358637. Xylose reductase catalyzes the NAD(P)H-dependent reduction of xylose to xylitol and is essential for growth on xylose by yeasts. Paper-1338170. The reduced xylitol yield was accompanied by reduced glycerol and acetate formation suggesting enhanced utilization of NADH in the XR reaction. Paper-9021358. The dual cofactor specificity of XR, with a preference for NADPH over NADH, was evident from the effects of xylose reduction on product fluxes. Paper-496406. A P. stipitis cDNA library in lambda gt11 was screened using antisera against P. stipitis xylose reductase and xylitol dehydrogenase, respectively. Paper-28446. Enzymatic assays indicated that C. milleri does not possess xylitol dehydrogenase activity and its xylose reductase is exclusively NADPH-dependent. Paper-8585300. Xylose reductase (E.C. 1.1.1.21) is a key enzyme responsible for xylose metabolism in xylose-utilizing as well as xylose-fermenting yeasts. Paper-12928. S. cerevisiae carrying the xylose reductase gene could not, however, grow on xylose medium, and could not produce ethanol from xylose. Paper-42428. Changing flux of xylose metabolites by altering expression of xylose reductase and xylitol dehydrogenase in recombinant Saccharomyces cerevisiae. Paper-9756827. When grown on xylose under aerobic conditions, the strain with pXOR had up to 1.8-fold higher xylose reductase ( XOR) activity than the control strain. Paper-577623. The bound-state equilibrium constant for C. tenuis xylose reductase is estimated to be approximately 45 (=170/3.8), thus greatly favoring aldehyde reduction. Paper-9049545. RESULTS: Site-specific mutagenesis of H. polymorpha XYL1 gene encoding xylose reductase was carried out to decrease affinity of this enzyme toward NADPH. Paper-12967064. This resulted in significant increase in the KM for NADPH in the mutated xylose reductase (K341 --> R N343 --> D), while KM for NADH remained nearly unchanged. Paper-12967064. The Pichia stipitis CBS 6054 genes XYL1 and XYL2 encoding xylose reductase and xylitol dehydrogenase were cloned into S. cerevisiae. Paper-444438. Effect of enhanced xylose reductase activity on xylose consumption and product distribution in xylose-fermenting recombinant Saccharomyces cerevisiae. Paper-9699330. Xylitol was formed by the XR- XDH-carrying strains only in mineral medium, whereas in lignocellulose hydrolysate no xylitol formation was detected. Paper-13110555. Saccharomyces cerevisiae is able to ferment xylose, when engineered with the enzymes xylose reductase (XYL1) and xylitol dehydrogenase ( XYL2). Paper-10679829. Increased xylose and arabinose reductase activity was observed in cell extracts for S. cerevisiae overexpressing the GRE3, YPR1 and YJR096w genes. Paper-9333883. Xylose reductase is a homodimeric oxidoreductase dependent on NADPH or NADH and belongs to the largely monomeric aldo-keto reductase superfamily of proteins. Paper-9505444. When grown on glucose under aerobic or oxygen-limited conditions, the experimental strain had XOR activity up to 10 times higher than that of the control strain. Paper-577623. Xylose reductase appears to be a xylose inducible enzyme and xylitol dehydrogenase activity is constitutive, although both are repressed by glucose. Paper-12800800. Biomass was reduced by 31% in strains where GRE3 was deleted, suggesting that fine-tuning of GRE3 expression is the preferred choice rather than deletion. Paper-10384548. Exploring the active site of yeast xylose reductase by site-directed mutagenesis of sequence motifs characteristic of two dehydrogenase/reductase family types. Paper-9014013. Xylitol production results from a cofactor imbalance, since xylose reductase uses both NADPH and NADH, while xylitol dehydrogenase uses only NAD(+). Paper-9414302. Transient-state and steady-state kinetic studies of the mechanism of NADH-dependent aldehyde reduction catalyzed by xylose reductase from the yeast Candida tenuis. Paper-9049545. Comparison of the xylose reductase- xylitol dehydrogenase and the xylose isomerase pathways for xylose fermentation by recombinant Saccharomyces cerevisiae. Paper-13110555. A sudden overaccumulation of methylglyoxal (MG) induces, in Saccharomyces cerevisiae, the expression of MG-protective genes, including GPD1, GLO1 and GRE3. Paper-11027043. The most enhanced ethanol yield and lowered xylitol yield occurred in strain I-PGK/AUR, which has high activity of both XR and XDH and moderate XK activity. Paper-13044997. Efficient bioethanol production from xylose by recombinant saccharomyces cerevisiae requires high activity of xylose reductase and moderate xylulokinase activity. Paper-13044997. Reduced xylitol formation from D-xylose in gre3 mutants of S. cerevisiae suggests that Gre3p is the major D-xylose-reducing enzyme in S. cerevisiae. Paper-9333883. This work was carried out to assess physiological consequences in xylose-fermenting S. cerevisiae resulting from a well defined alteration of XR cosubstrate specificity. Paper-12783461. Fermentation with strain S103-TAL, having a xylose reductase/ xylitol dehydrogenase ratio of 0.5:30 compared with 4.2:5.8 for S104-TAL, did not prevent xylitol formation. Paper-444438. Ethanol production from xylose by recombinant Saccharomyces cerevisiae expressing protein-engineered NADH-preferring xylose reductase from Pichia stipitis. Paper-13419550. Maximal specific growth rates on glucose were lower in the ZWF1-disrupted strains, and the increased XR activity also negatively affected the growth rate in these strains. Paper-9699330. Analysis of the deduced amino acid sequences indicated that GRE1, GRE2 and GRE3 correspond to ORFs YPL223C, YOL151W and YHR104W, respectively. Paper-1981586. Decreased arabitol formation from L-arabinose indicates that Gre3p, Ypr1p and the protein encoded by YJR096w are the major arabinose reducers in S. cerevisiae. Paper-9333883. CONCLUSION: We demonstrate for the first time that xylose reductase is also able to reduce the furaldehyde compounds that are present in undetoxified lignocellulosic hydrolysates. Paper-12882276. The amino acid sequence of the P. stipitis XR is similar to several aldose reductases, suggesting that P. stipitis XR is part of the aldoketo reductase superfamily. Paper-44965. This conclusion is supported by the observation that anaerobic xylose utilization is observed only in those yeasts which possess a high activity of an NADH-linked xylose reductase. Paper-5318222. It has been suggested, however, that NADPH-dependent XRs, including the XR of C. tropicalis, are limited by the coenzyme availability and thus limit the production of xylitol. Paper-10068374. However, the xylitol yield was lower in these strains than in strains expressing only native XR and XDH monomers, 0.55 and 0.62, respectively, and the ethanol yield was higher. Paper-9021358. We previously showed that a cystein residue may be involved in binding of the coenzyme NADPH to the Pichia stipitis xylose reductase through chemical modification studies. Paper-954345. Expression of bifunctional enzymes with xylose reductase and xylitol dehydrogenase activity in Saccharomyces cerevisiae alters product formation during xylose fermentation. Paper-9021358. These results indicate that the SDR-like Gly motif likely provides support to the overall structure of the enzyme, but it does not contribute directly to coenzyme binding in this XR. Paper-12064887. An endogenous aldo-keto reductase, encoded by the GRE3 gene, was expressed at different levels in recombinant S. cerevisiae strains to investigate its effect on xylose utilization. Paper-10384548. Similarly, expression of GAPN in a strain harbouring xylose reductase and xylitol dehydrogenase led to an improvement in ethanol yield by up to 25% on xylose/glucose mixtures. Paper-11323182. Cloning and expression in Saccharomyces cerevisiae of the NAD(P)H-dependent xylose reductase-encoding gene ( XYL1) from the xylose-assimilating yeast Pichia stipitis. Paper-48715. The effect was associated with the ability of D-fructose to repress the induction of xylose reductase and xylitol dehydrogenase activities in P. tannophilus but not in P. stipitis. Paper-6485336. Finally, induction of GPD1, TPS1 and GRE3, and enhanced MG contents were also observed in low-glucose-growing cells subjected to a sudden increase in glucose availability. Paper-10240939. Deletion of the GRE3 aldose reductase gene and its influence on xylose metabolism in recombinant strains of Saccharomyces cerevisiae expressing the xylA and XKS1 genes. Paper-10720553. Results of our chemical modification and site-directed mutagenesis study indicated that Lys270 is involved in both NADPH and D-xylose binding in the P. stipitis xylose reductase. Paper-1338170. The metabolic network analysis with 13C labelled glucose showed that there was a shift in the specific xylose reductase activity towards use of NADH as co-factor rather than NADPH. Paper-11626944. Saccharomyces cerevisiae L2612 transformed with genes for xylose reductase and xylitol dehydrogenase ( XYL1 and XYL2) grows well on glucose but very poorly on d-xylose. Paper-13164173. Altering the coenzyme preference of xylose reductase to favor utilization of NADH enhances ethanol yield from xylose in a metabolically engineered strain of Saccharomyces cerevisiae. Paper-12783461. A xylose reductase gene was isolated from the xylose-fermenting yeast Pachysolen tannophilus as a cDNA clone by selecting clones that hybridized specifically to xylose-inducible messenger RNA. Paper-882303. This is the first report of the cloning of an xyl1 gene encoding an NADH-preferring XR and its functional expression in C. tropicalis, a yeast currently used for industrial production of xylitol. Paper-10068374. At low temperatures, the xylose reductase was expressed in soluble and active form up to about 10% of the soluble protein; with rising temperatures formation of visible inclusion bodies occurred. Paper-2117859. Engineering of xylose reductase and overexpression of xylitol dehydrogenase and xylulokinase improves xylose alcoholic fermentation in the thermotolerant yeast Hansenula polymorpha. Paper-12967064. In nontransformed S. cerevisiae strains, XDH activity was significantly higher in the presence of xylose, but xylose reductase ( XR) activity was not affected by the choice of carbon source. Paper-10335309. Furthermore, addition of NaCl or H2O2 to exponential-phase cells triggers an initial transient increase in the intracellular level of methylglyoxal, which is dependent on the Gre3p and Glo1p function. Paper-8897977. The isotope effect data suggest a chemical mechanism of carbonyl reduction by xylose reductase in which transfer of hydride ion is a partially rate-limiting step and precedes the proton-transfer step. Paper-9049545. Saccharomyces cerevisiae, an efficient ethanol producer, can utilize xylose only when expressing the heterologous genes XYL1 ( xylose reductase) and XYL2 ( xylitol dehydrogenase). Paper-8938528. Xylitol production from xylose was studied using recombinant Saccharomyces cerevisiae 2805 containing xylose reductase genes (XYL1) of Pichia stipitis at chromosomal delta-sequences. Paper-1776764. We obtained efficient conversion of xylose to xylitol by transforming Saccharomyces cerevisiae with the gene encoding the xylose reductase ( XR) of Pichia stipitis CBS 6054. Paper-44965. Xylose growth had not previously been detected in strains in which the PPP genes were not overexpressed or when overexpressing the PPP genes but having XR and XDH genes chromosomally integrated. Paper-10762605. CtXR ( xylose reductase from the yeast Candida tenuis; AKR2B5) can utilize NADPH or NADH as co-substrate for the reduction of D-xylose into xylitol, NADPH being preferred approx. 33-fold. Paper-11297677. The specific activity of xylose reductase and xylitol dehydrogenase was also higher for S. cerevisiae TMB 3400 than for TMB 3399, both on glucose and on the mixture of glucose and xylose. Paper-9851764. The positive effect of the decreased NADPH-preferring activity of xylose reductase from Pichia stipitis on ethanol production using xylose-fermenting recombinant Saccharomyces cerevisiae. Paper-13252180. The results indicate that ethanolic xylose fermentation by recombinant S. cerevisiae expressing XR and XDH is governed by the efficiency by which xylose is introduced in the central metabolism. Paper-12378852. Xylose reductase from the xylose-fermenting yeast Pichia stipitis was purified to electrophoretic and spectral homogeneity via ion-exchange, affinity and high-performance gel chromatography. Paper-5106026. Multiple forms of xylose reductase in Candida intermedia: comparison of their functional properties using quantitative structure-activity relationships, steady-state kinetic analysis, and pH studies. Paper-10095487. A constitutive non-glucose-repressible NADPH2-dependent xylose reductase with a specific activity of ca. 5 mU/mg of protein that converted xylose to xylitol was present in a glucose-grown culture. Paper-93069. Kinetic substituent effects have been used to examine the catalytic reaction profile of xylose reductase from the yeast Candida tenuis, a representative aldo/keto reductase of primary carbohydrate metabolism. Paper-9547487. Preliminary kinetic characterization of xylose reductase and xylitol dehydrogenase extracted from Candida guilliermondii FTI 20037 cultivated in sugarcane bagasse hydrolysate for xylitol production. Paper-10726215. The mutagenized XYL2 gene could still mediate growth of Saccharomyces cerevisiae transformants on xylose minimal-medium plates when expressed together with the xylose reductase gene ( XYL1). Paper-177280. The strain with XR/XDH ratio of 0.06 consumed 3.25 g/ L xylose and formed no xylitol and less glycerol and acetic acid, but more ethanol compared with the strains with a higher XR/XDH ratio. Paper-1520773. Xylose reductase and xylitol dehydrogenase activities of Candida guilliermondii as a function of different treatments of sugarcane bagasse hemicellulosic hydrolysate employing experimental design. Paper-9546597. These results, in combination with those obtained with the deletion mutants, suggest that Gre3p, Ypr1p and the protein encoded by YJR096w are capable of xylose and arabinose reduction in S. cerevisiae. Paper-9333883. The strain harboring the XR double mutant showed 42% enhanced ethanol yield (0.34 g/g) compared to the reference strain harboring wild-type XR during anaerobic bioreactor conversions of xylose (20 g/L). Paper-12783461. Comparison of the chromosomal and cDNA copies of the XYL1 gene showed that the genomic XYL1 contains no introns, and an XR monomer of 318 amino acids (35,985 D) is encoded by an open reading frame of 954 bp. Paper-44965. In the Saccharomyces cerevisiae xylose reductase ( XR), the SDR-like coenzyme-binding GXXXGXG motif ( Gly motif) is located between residues 128 and 134, with the third Gly residue being replaced by an Asp. Paper-12064887. Conversion of xylose to xylitol by recombinant Saccharomyces cerevisiae expressing the XYL1 gene, encoding xylose reductase, was investigated by using different cosubstrates as generators of reduced cofactors. Paper-1018960. CONCLUSION: Despite by-product formation, the XR- XDH xylose utilization pathway resulted in faster ethanol production than using the best presently reported XI pathway in the strain background investigated. Paper-13110555. Because XR requires about 10-fold less xylose and cofactor than XD for the condition in which the reaction rate is half of the Vmax, some interference on the overall xylitol production by the yeast could be expected. Paper-10726215. The apparent K(M) for XR and XD against substrates and cofactors were as follows: for XR, 6.4 x 10(-2)M ( xylose) and 9.5 x 10(-3) mM ( NADPH); for XD, 1.6 x 10(-1)M ( xylitol) and 9.9 x 10(-2) mM ( NAD+). Paper-10726215. S. cerevisiae cells transformed with a plasmid, pRD1, containing both the xylose reductase gene (XYL1) and the xylitol dehydrogenase gene ( XYL2), were able to grow on xylose as a sole carbon source. Paper-28446. In this study the ability of various sugars and sugar alcohols to induce aldose reductase ( xylose reductase) and xylitol dehydrogenase ( xylulose reductase) activities in the yeast Candida tenuis was investigated. Paper-1008329. An S. cerevisiae strain carrying the XR and XDH enzymes from the xylose-utilizing yeast Pichia stipitis grew more quickly and accumulated less xylitol than did the strain overexpressing the endogenous enzymes. Paper-10335309. Overexpression of the GRE3 and ScXYL2 genes in the S. cerevisiae CEN.PK2 strain resulted in a growth rate of 0.01 g of cell dry mass liter(-1) h(-1) and a xylitol yield of 55% when xylose was the main carbon source. Paper-10335309. Expression of heterologous xylose reductase and xylitol dehydrogenase does enable D-xylose utilisation, but intrinsic redox constraints of this pathway result in undesirable byproduct formation in the absence of oxygen. Paper-12488948. Xylose reductase (XR; AKR2B5) is an unusual member of aldo-keto reductase superfamily, because it is one of the few able to efficiently utilize both NADPH and NADH as co-substrates in converting xylose into xylitol. Paper-9779084. However, the nucleotide sequence immediately adjacent to the initiation codon of XR, which controls the translation of the gene product, seemed to be five times less effective than the corresponding sequence of the ADC1 gene. Paper-94384. When xylose metabolism in yeasts proceeds exclusively via NADPH-specific xylose reductase and NAD-specific xylitol dehydrogenase, anaerobic conversion of the pentose to ethanol is intrinsically impossible. Paper-10240941. Xylulokinase overexpression in two strains of Saccharomyces cerevisiae also expressing xylose reductase and xylitol dehydrogenase and its effect on fermentation of xylose and lignocellulosic hydrolysate. Paper-8938528. When xylose reductase has a dual specificity for both NADPH and NADH, anaerobic alcoholic fermentation is feasible but requires the formation of large amounts of polyols (e.g., xylitol) to maintain a closed redox balance. Paper-10240941. The structures of the Candida tenuis xylose reductase apo- and holoenzyme, which crystallize in spacegroup C2 with different unit cells, have been determined to 2.2 A resolution and an R-factor of 17.9 and 20.8%, respectively. Paper-9505444. Introduction of a xylose pathway into an arabinose-fermenting laboratory strain resulted in nearly complete conversion of arabinose into arabitol due to the L-arabinose reductase activity of the xylose reductase. Paper-12001173. The gene XYL1, encoding a xylose reductase, from Pichia stipitis was transformed into a mutant of Saccharomyces cerevisiae incapable of glycerol production because of deletion of the genes GPD1 and GPD2. Paper-756092. The recombinant xylose-utilizing Saccharomyces cerevisiae TMB 3399 was constructed by chromosomal integration of the genes encoding D-xylose reductase ( XR), xylitol dehydrogenase (XDH), and xylulokinase ( XK). Paper-9733624. This study focused on elucidating metabolism of xylose in a Saccharomyces cerevisiae strain that overexpresses xylose reductase and xylitol dehydrogenase from Pichia stipitis, as well as the endogenous xylulokinase. Paper-10026552. Sensitivity of the P. stipitis xylose reductase to thiol-specific reagents was attributed to both Cys27 and Cys130 residues as substitution of either residue with Ser resulted in a significant but incomplete loss of sensitivity to PCMBS. Paper-954345. XR activity remained stable for 3 h under 4 and 38 degrees C and for 4 months of storage at -18 degrees C. Studies on cofactor specificity showed that only NADPH-dependent XR was obtained under the cultivation conditions employed. Paper-12008516. At the end of the fermentation, the fraction of plasmid bearing cells in the beads was close to 100% for the low XR strain; however, it was significantly lower for the high XR strain, particularly for cells from the interior of the beads. Paper-12808791. Recombinant strains containing genes coding for xylose reductase ( XR) and xylitol dehydrogenase (XDH) from the xylose-utilizing yeast Pichia stipitis have been reported; however, such strains ferment xylose to ethanol poorly. Paper-9021359. Saccharomyces cerevisiae mutants, in which open reading frames ( ORFs) displaying similarity to the aldo-keto reductase GRE3 gene have been deleted, were investigated regarding their ability to utilize xylose and arabinose. Paper-9333883. 5. The xylose reductase (EC 1.1.1.21) and xylitol dehydrogenase (EC 1.1.1.9) activities were determined in some of the isolates as well as in two strains of S. cerevisiae (ATCC 24860 and baker's yeast) and Pichia stipitis CBS 6054. Paper-63838. Saccharomyces cerevisiae TMB3001 has previously been engineered to utilize xylose by integrating the genes coding for xylose reductase ( XR) and xylitol dehydrogenase (XDH) and overexpressing the native xylulokinase ( XK) gene. Paper-10017857. Recombinant Saccharomyces cerevisiae TMB3001, harboring the Pichia stipitis genes XYL1 and XYL2 ( xylose reductase and xylitol dehydrogenase, respectively) and the endogenous XKS1(xylulokinase), can convert xylose to ethanol. Paper-9699330. The transformed strain was capable of anaerobic glucose conversion in the presence of added xylose, indicating that the xylose reductase reaction can fulfill the role of the glycerol-3-phosphate dehydrogenase reaction as a redox sink. Paper-756092. Xylitol can be obtained by microbiological process, since many yeasts and filamentous fungi synthesize the xylose reductase enzyme, which catalyses the xylose reduction into xylitol as the first step in the xylose metabolism. Paper-1517760. Continuous xylitol production with two different immobilized recombinant Saccharomyces cerevisiae strains (H475 and S641), expressing low and high xylose reductase ( XR) activities, was investigated in a lab-scale packed-bed bioreactor. Paper-12808791. We changed the fluxes of xylose metabolites in recombinant Saccharomyces cerevisiae by manipulating expression of Pichia stipitis genes (XYL1 and XYL2) coding for xylose reductase ( XR) and xylitol dehydrogenase (XDH), respectively. Paper-9756827. Incomplete recycling of redox cosubstrates in the catalytic steps of the NADPH-preferring XR and the NAD+-dependent XDH results in formation of xylitol by-product and hence in lowering of the overall yield of ethanol on xylose. Paper-12783461. We focused on the effects of a mutation of xylose reductase from Pichia stipitis (PsXR) on xylose-to-ethanol fermentation using recombinant Saccharomyces cerevisiae transformed with PsXR and PsXDH ( xylitol dehydrogenase from P. stipitis) genes. Paper-13252180. Evidence is presented that xylose metabolism in the anaerobic cellulolytic fungus Piromyces sp. E2 proceeds via a xylose isomerase rather than via the xylose reductase/xylitol-dehydrogenase pathway found in xylose-metabolising yeasts. Paper-10666846. BACKGROUND: Two heterologous pathways have been used to construct recombinant xylose-fermenting Saccharomyces cerevisiae strains: i) the xylose reductase ( XR) and xylitol dehydrogenase ( XDH) pathway and ii) the xylose isomerase (XI) pathway. Paper-13110555. We found that S. cerevisiae can grow on D-xylose when only the endogenous genes GRE3 (YHR104w), coding for a nonspecific aldose reductase, and XYL2 (YLR070c, ScXYL2), coding for a xylitol dehydrogenase (XDH), are overexpressed under endogenous promoters. Paper-10335309. In a recombinant S. cerevisiae strain producing only xylitol dehydrogenase (XDH) from P. stipitis and an extra copy of the endogenous xylulokinase ( XK), ethanol formation from xylose was mediated by Gre3p, capable of reducing xylose to xylitol. Paper-10384548. Furthermore, isolation and analysis of plasmids from a population that had lost its XR activity, showed that in addition to the original plasmid, a rearranged form of the plasmid, retaining the selection marker but not the expression of active XR, was present. Paper-12809572. Autoselective xylose-utilising strains of Saccharomyces cerevisiae expressing the xylose reductase (XYL1) and xylitol dehydrogenase ( XYL2) genes of Pichia stipitis were constructed by replacing the chromosomal FUR1 gene with a disrupted fur1::LEU2 allele. Paper-2091914. The xylose reductase gene ( XYL1) was isolated from Pichia stipitis and |