Information on EC 1.1.1.307 - D-xylose reductase

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The expected taxonomic range for this enzyme is: Eukaryota, Bacteria

EC NUMBER
COMMENTARY
1.1.1.307
-
RECOMMENDED NAME
GeneOntology No.
D-xylose reductase
-
PATHWAY
KEGG Link
MetaCyc Link
Metabolic pathways
-
Pentose and glucuronate interconversions
-
SYSTEMATIC NAME
IUBMB Comments
xylitol:NAD(P)+ oxidoreductase
Xylose reductase catalyses the initial reaction in the xylose utilization pathway, the NAD(P)H dependent reduction of xylose to xylitol.
SYNONYMS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
CtXR
O74237
-
CtXR
C1K8Y9
-
D-xylose reductase
-
-
D-xylose reductase 1
-
-
D-xylose reductase 1
Candida tropicalis IF0 0618
-
-
-
D-xylose reductase 2
-
-
D-xylose reductase 2
Candida tropicalis IF0 0618
-
-
-
D-xylose reductase 3
-
-
D-xylose reductase 3
Candida tropicalis IF0 0618
-
-
-
dsXR
-
Candida intermedia produces two isoforms of xylose reductase: one is NADPH-dependent (monospecific xylose reductase, msXR), and another prefers NADH about 4fold over NADPH (dual specific xylose reductase, dsXR)
msXR
-
Candida intermedia produces two isoforms of xylose reductase: one is NADPH-dependent (monospecific xylose reductase, msXR), and another prefers NADH about 4fold over NADPH (dual specific xylose reductase, dsXR)
NAD(P)H-dependent xylose reductase
-
-
NAD(P)H-dependent xylose reductase
-
-
NADPH-preferring xylose reductase
-
-
NADPH-preferring xylose reductase
Kluyveromyces marxianus YHJ010
-
-
-
XR1
Candida tropicalis IF0 0618
-
-
-
XR2
Candida tropicalis IF0 0618
-
-
-
XYL1
Candida parapsilosis KFCC-10875
Q6Y0Z3
-
-
XYL1
C1K8Y9
gene name
xylose reductase
-
-
xylose reductase
-
-
xylose reductase
-
-
xylose reductase
Candida tropicalis ATCC 20336
-
-
-
xylose reductase
-
-
xylose reductase
Kluyveromyces marxianus YHJ010
-
-
-
xylose reductase
Meyerozyma guilliermondii FTI, Meyerozyma guilliermondii FTI 20037
-
-
-
xylose reductase
-
-
xylose reductase
F2YCN5
-
xylose reductase
Zymomonas mobilis ZM4
F2YCN5
-
-
XylR
O74237
-
XylR
Candida tenuis CBS 4435
O74237
-
-
XyrA
Q9P8R5
-
ORGANISM
COMMENTARY
LITERATURE
SEQUENCE CODE
SEQUENCE DB
SOURCE
strain F-3
-
-
Manually annotated by BRENDA team
Candida diddensiae F-3
strain F-3
-
-
Manually annotated by BRENDA team
KFCC-10875
SwissProt
Manually annotated by BRENDA team
Candida parapsilosis KFCC-10875
KFCC-10875
SwissProt
Manually annotated by BRENDA team
strain Y-1632
-
-
Manually annotated by BRENDA team
Candida shehatae Y-1632
strain Y-1632
-
-
Manually annotated by BRENDA team
strain VGI-II
-
-
Manually annotated by BRENDA team
Candida silvanorum VGI-II
strain VGI-II
-
-
Manually annotated by BRENDA team
strain CBS 4435
SwissProt
Manually annotated by BRENDA team
Candida tenuis CBS 4435
strain CBS 4435
SwissProt
Manually annotated by BRENDA team
IF0 0618
-
-
Manually annotated by BRENDA team
SCTCC 300249
UniProt
Manually annotated by BRENDA team
strain Y-456
-
-
Manually annotated by BRENDA team
Candida tropicalis ATCC 20336
-
-
-
Manually annotated by BRENDA team
Candida tropicalis IF0 0618
IF0 0618
-
-
Manually annotated by BRENDA team
Candida tropicalis SCTCC 300249
SCTCC 300249
UniProt
Manually annotated by BRENDA team
Candida tropicalis Y-456
strain Y-456
-
-
Manually annotated by BRENDA team
Corynebacterium glutamicum ATCC13032
gene XYL1
-
-
Manually annotated by BRENDA team
strain UFV-170 XR
-
-
Manually annotated by BRENDA team
Debaryomyces hansenii UFV-170 XR
strain UFV-170 XR
-
-
Manually annotated by BRENDA team
Kluyveromyces marxianus Y-488
Y-488
-
-
Manually annotated by BRENDA team
Kluyveromyces marxianus YHJ010
-
-
-
Manually annotated by BRENDA team
FTI 20037, ATCC 201935
-
-
Manually annotated by BRENDA team
strain Y-1017
-
-
Manually annotated by BRENDA team
Meyerozyma guilliermondii FTI 20037
FTI 20037
-
-
Manually annotated by BRENDA team
Meyerozyma guilliermondii Y-1017
strain Y-1017
-
-
Manually annotated by BRENDA team
strain Y-1532, strain Y-1533, strain Y-1634
-
-
Manually annotated by BRENDA team
Saccharomyces cerevisiae TMB 3420
-
-
-
Manually annotated by BRENDA team
strain Y-2160
-
-
Manually annotated by BRENDA team
Scheffersomyces stipitis Y-2160
strain Y-2160
-
-
Manually annotated by BRENDA team
Torulopsis molishiama
strain 55
-
-
Manually annotated by BRENDA team
Torulopsis molishiama 55
strain 55
-
-
Manually annotated by BRENDA team
ssp. mobilis, and strain A3, an engineered strain ZM4 that is adapted to 5% D-xylose, gene ZMO0976
UniProt
Manually annotated by BRENDA team
Zymomonas mobilis ZM4
ssp. mobilis, and strain A3, an engineered strain ZM4 that is adapted to 5% D-xylose, gene ZMO0976
UniProt
Manually annotated by BRENDA team
GENERAL INFORMATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
metabolism
-
xylose reductase in the xylitol-producing species Candida didensiae, Candida intermediae, Candida parapsilosis, Candida silvanorum, Candida tropicalis, Kluyveromyces fragilis, Kluyveromyces marxianus, Pichia guillermondii, and Torulopsis molishiama is specific for NADPH. Xylose reductase in the ethanol-producing species Pichia stipitis, Candida shehatae, and Pachysolen tannophilus is specific for both NADPH and NADH. Pachysolen tannophilus strains, whose xylose reductases are almost equally specific for NADH and NADPH, produce xylitol and ethanol in comparable amounts, while Candida shehatae and Pichia stipitis, whose xylose reductases are more specific for NADH than for NADPH, produce predominantly ethanol
metabolism
-
key enzymes for xylitol production in yeasts are xylose reductase and xylitol dehydrogenase, EC 1.1.1.9, overview
metabolism
-
xylose reductase is the first enzyme in D-xylose metabolism, catalyzing the reduction of D-xylose to xylitol
metabolism
Candida diddensiae F-3, Candida shehatae Y-1632, Candida silvanorum VGI-II
-
xylose reductase in the xylitol-producing species Candida didensiae, Candida intermediae, Candida parapsilosis, Candida silvanorum, Candida tropicalis, Kluyveromyces fragilis, Kluyveromyces marxianus, Pichia guillermondii, and Torulopsis molishiama is specific for NADPH. Xylose reductase in the ethanol-producing species Pichia stipitis, Candida shehatae, and Pachysolen tannophilus is specific for both NADPH and NADH. Pachysolen tannophilus strains, whose xylose reductases are almost equally specific for NADH and NADPH, produce xylitol and ethanol in comparable amounts, while Candida shehatae and Pichia stipitis, whose xylose reductases are more specific for NADH than for NADPH, produce predominantly ethanol
-
metabolism
Candida tropicalis ATCC 20336
-
xylose reductase is the first enzyme in D-xylose metabolism, catalyzing the reduction of D-xylose to xylitol
-
metabolism
Candida tropicalis Y-456, Kluyveromyces marxianus Y-488, Meyerozyma guilliermondii Y-1017, Scheffersomyces stipitis Y-2160, Torulopsis molishiama 55
-
xylose reductase in the xylitol-producing species Candida didensiae, Candida intermediae, Candida parapsilosis, Candida silvanorum, Candida tropicalis, Kluyveromyces fragilis, Kluyveromyces marxianus, Pichia guillermondii, and Torulopsis molishiama is specific for NADPH. Xylose reductase in the ethanol-producing species Pichia stipitis, Candida shehatae, and Pachysolen tannophilus is specific for both NADPH and NADH. Pachysolen tannophilus strains, whose xylose reductases are almost equally specific for NADH and NADPH, produce xylitol and ethanol in comparable amounts, while Candida shehatae and Pichia stipitis, whose xylose reductases are more specific for NADH than for NADPH, produce predominantly ethanol
-
METALS and IONS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
CaCl2
Q6Y0Z3
1 mM, stimulates
CoCl2
Q6Y0Z3
1 mM, stimulates
FeCl2
Q6Y0Z3
1 mM, stimulates
Li+
A0MTG4
Ca2+, Li+, Mg2+, Mn2+ and NH4+ at 10 mM decrease activity by 10-50%
Mg2+
A0MTG4
Ca2+, Li+, Mg2+, Mn2+ and NH4+ at 10 mM decrease activity by 10-50%
MgCl2
Q6Y0Z3
1 mM, stimulates
Mn2+
A0MTG4
Ca2+, Li+, Mg2+, Mn2+ and NH4+ at 10 mM decrease activity by 10-50%
NH4+
A0MTG4
Ca2+, Li+, Mg2+, Mn2+ and NH4+ at 10 mM decrease activity by 10-50%
NiCl2
Q6Y0Z3
1 mM, stimulates
ZnCl2
Q6Y0Z3
1 mM, stimulates
MnCl2
Q6Y0Z3
1 mM, stimulates
additional information
-
no effect: Na+, K+, NH4+, Mg2+, Ca2+ and Co2+ in the form of the chloride salt in 50 mM Tris, pH 7.0, as well the anions PO43-, SO32-, NO3-, CO32-, citrate and tetraborate in the form of the sodium salt in 50 mM phosphate buffer, pH 7.0
additional information
Q6Y0Z3
neither inhibited nor activated by EDTA at concentrations ranging from 1 to 10 mM
additional information
-
no effect: 1 mM CuSO4
additional information
-
no requirement for divalent cation is observed
additional information
A9QVV8
no increase in activity in presence of 1 mM NaCl and 1 mM MgSO4
INHIBITORS
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
AMP
-
2 mM, completely abolishes D-xylose reduction
ATP
-
2 mM, completely abolishes D-xylose reduction, competitive
cholic acid
-
0.1% (w/v), 30% inhibition
Cu2+
Q6Y0Z3
activity is completely restored by addition of EDTA
deoxycholic acid
-
0.1% (w/v), 30% inhibition
dithiothreitol
-
1 mM, 40% inhibition
dithiothreitol
-
1 mM, 25% inhibition
DTT
A0MTG4
1 mM, 35% inhibition
EDTA
-
1 mM, 30% inhibition
Hg2+
-
0.001 mM, 2 min, complete inhibition
N-bromosuccinimide
-
NADPH protects
NaCl
-
50 mM, 25% inhibition
NAD+
Q6Y0Z3
competitive with NADH, non-competitive with D-xylose
NAD+
-
strong inhibition with the NADH-linked reaction, no inhibition of NADPH-linked reaction. NAD+ is a non-competitive inhibitor with respect to xylose and a competitive inhibitor with respect to NADH
NADP+
-
2 mM completely abolishes D-xylose reduction. Potent competitive inhibitor, inhibits both the NADH-dependent and the NADPH-dependent activity
NADP+
-
potent inhibitor of both the NADPH- and NADH-linked xylose reduction. Competition with NADPH and non-competitive inhibition with xylose in the NADPH-linked xylose reduction
NADP+
-
for monospecific xylose reductase (msXR) and dual specific xylose reductase (dsXR) NADP+ behaves as a competitive inhibitor against NADPH. Competitive inhibition of is observed both at unsaturating and saturating concentrations of xylose
NADPH
-
for monospecific xylose reductase (msXR) and dual specific xylose reductase (dsXR) NADPH behaves as a competitive inhibitor against NADP+. Competitive inhibition of is observed both at unsaturating and saturating concentrations of xylitol
p-chloromercuribenzoate
-
0.001 mM, 2 min, complete inhibition
pyridoxal 5'-phosphate
-
gradual inactivation. NADH, ATP or 2'-AMP protects. No protection by D-xylose
sodium phosphite
-
200 mM, 37% inhibition
xylitol
Q6Y0Z3
non-competitive against NADH and D-xylose
Zn2+
-
25 mM, 95% inhibition
Mn2+
-
25 mM, 95% inhibition
additional information
-
no inhibition by NAD+. No effect: Na+, K+, NH4+, Mg2+, Ca2+ and Co2+ in the form of the chloride salt in 50 mM Tris, pH 7.0, as well the anions Cl-, PO43-, SO32-, NO3-, CO32-, citrate and tetraborate in the form of the sodium salt in 50 mM phosphate buffer, pH 7.0. Glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, 6-phosphogluconate, phosphoenolpyruvate, oxaloacetate (5 mM each) have no effect
-
additional information
-
no effect 0.1% w/v sodium azide
-
additional information
-
no effect by 5 mM EDTA, 500 mM sulfate, 5 mM 2-mercaptoethanol
-
ACTIVATING COMPOUND
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
2-mercaptoethanol
Q6Y0Z3
1 mM, increases activity by 13%
Bovine serum albumin
-
0.1% (w/v), 10-15% activation
-
Bovine serum albumin
-
1 mg/ml, 30% activation
-
Bovine serum albumin
A0MTG4
1 mg/ml. the specific activity is increased by 20-30%
-
Bovine serum albumin
A9QVV8
1 mg/ml, 20% increase of activity
-
cysteine
Q6Y0Z3
1 mM, increases activity by 29%
dithiothreitol
Q6Y0Z3
1 mM, increases activity by 43%
DTT
A9QVV8
1 mM, 27% increase of activity
EDTA
-
1 mM, 5% activation
EDTA
A0MTG4
1 mM, 30% activation
Triton X-100
-
0.1% (w/v), 10-15% activation
Triton X-100
A0MTG4
0.1%, the specific activity is increased by 2030%
Tween 20
A0MTG4
0.1%, the specific activity is increased by 20-30%
Tween 80
A0MTG4
0.1%, the specific activity is increased by 20-30%
Tween-20
-
0.1% (w/v), 10-15% activation
Tween-80
-
0.1% (w/v), 10-15% activation
glutathione
Q6Y0Z3
1 mM, increases activity by 21%
additional information
Q6Y0Z3
neither inhibited nor activated by EDTA at concentrations ranging from 1 to 10 mM
-
Ki VALUE [mM]
Ki VALUE [mM] Maximum
INHIBITOR
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
IMAGE
0.0239
-
ATP
-
pH 7, 25C, variable substrate: NADH
0.034
-
Cu2+
Q6Y0Z3
pH 6.0
0.074
-
NAD+
-
pH 7.0, 25C, dual specific xylose reductase (dsXR)
0.13
-
NAD+
-
concentration of NADH varied
0.18
-
NAD+
Q6Y0Z3
pH 6.0, competitive with NADH
0.195
-
NAD+
-
pH 7.0, 25C
0.325
-
NAD+
Q6Y0Z3
pH 6.0, non-competitive with D-xylose
0.65
-
NAD+
-
concentration of D-xylose varied
0.0019
-
NADH
-
pH 7.0, 25C
0.008
-
NADH
-
pH 7.0, 25C, dual specific xylose reductase (dsXR)
0.016
-
NADH
-
pH 7.0, 25C
0.02
-
NADH
-
pH 7.0, 25C, mutant enzyme D50A
0.02
-
NADH
-
pH 7.0, 25C, monospecific xylose reductase (msXR)
0.0015
-
NADP+
-
pH 7, 25C, variable substrate: NADH
0.006
-
NADP+
-
concentration of NADH varied
0.025
-
NADP+
-
pH 7.0, 25C, monospecific xylose reductase (msXR)
0.03
-
NADP+
-
concentration of NADPH varied
0.053
-
NADP+
-
pH 7.0, 25C, dual specific xylose reductase (dsXR)
0.17
-
NADP+
-
concentration of D-xylose varied
0.014
-
NADPH
-
pH 7.0, 25C, dual specific xylose reductase (dsXR)
pH RANGE
pH RANGE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
4
6.5
A9QVV8
pH 4.0: about 55% of maximal activity, pH 6.5: about 60% of maximal activity
4
7
-
pH 4.0: about 40% of maximal activity, pH 7.0: about 50% of maximal activity
4.5
7.5
-
pH 4.5: about 55% of maximal activity, pH 7.5: about 50% of maximal activity
5
7
Q6Y0Z3
pH 5.0: 81% of maximal activity, pH 7.0: about 65% of maximal activity
5
8
-
the ratio of activities with NADH and NADPH is approximately constant between pH 5 and 8
5
8
C5J3R6
; active from pH 5 to pH 8, wild-type and double-mutant (K271R/N273D) protein
TEMPERATURE RANGE
TEMPERATURE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
25
40
-
activity increases linearly from 25C to 50C
25
65
-
25C: about 55% of maximal activity, 65C: about 65% of maximal activity
30
60
C5J3R6
active from 30C to 60C, wild-type and double-mutant (K271R/N273D) protein
30
60
A9QVV8
30C: about 70% of maximal activity, 60C: about 45% of maximal activity
pI VALUE
pI VALUE MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
4.1
-
-
D-xylose reductase 2, isoelectric focusing, pH-range: 2.5-5.0
4.15
-
-
D-xylose reductase 1, isoelectric focusing, pH-range: 2.5-5.0
4.7
-
-
isoelectric focusing
5.1
-
C1K8Y9
calculated
5.19
-
Q6Y0Z3
calculated from sequence
SOURCE TISSUE
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
SOURCE
Candida diddensiae F-3, Candida shehatae Y-1632, Candida silvanorum VGI-II, Candida tropicalis Y-456, Kluyveromyces marxianus Y-488, Meyerozyma guilliermondii Y-1017, Scheffersomyces stipitis Y-2160, Torulopsis molishiama 55
-
microaerobically grown
-
Manually annotated by BRENDA team
additional information
-
the organism grows on rice straw hemicellulosic hydrolysate, as the only source of nutrient, optimization of culture conditions for production of xylitol from D-xylose, xylitol dehydrogenase remains constant, whereas the level of xylose reductase decreases when the initial xylose concentration is increased from 30 to 70 g/l, development of enzyme activities, overview
Manually annotated by BRENDA team
MOLECULAR WEIGHT
MOLECULAR WEIGHT MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
48000
-
-
gel filtration
53000
-
-
gel filtration
58000
-
-
D-xylose reductase 1, D-xylose reductase 2, D-xylose reductase 3, gel filtration
60000
-
-
gel filtration
63000
65000
-
gel filtration
69000
-
Q6Y0Z3
gel filtration
Crystallization/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
the purified N309D mutant is crystallized by the hanging-drop vapour-diffusion method at 25C. The best-diffracting crystals are grown using a well solution consisting of 2.1 M (NH4)2SO4, 100 mM sodium acetate and 100 mM sodium citrate, pH 6.4. Comparison of the 2.4 A X-ray crystal structure of mutant N309D bound to NAD+ with the previous structure of the wild-type holoenzyme reveals no major structural perturbations
-
hanging-drop vapour diffusion method, to 2.91 A resolution. Unit cell belongs to space group P31 or P32, presence of four XR molecules in the asymmetric unit, with 68.0% solvent content; hanging-drop vapour-diffusion method. X-ray diffraction data from xylose reductase crystals at 2.91 A resolution, the unit cell belongs to space group P3(1) or P3(2). Preliminary analysis indicates the presence of four xylose reductase molecules in the asymmetric unit, with 68.0% solvent content
C1K8Y9
pH STABILITY
pH STABILITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
5
8
-
below pH 5 and above pH 8.0 the enzyme is inactivated within 3-6 days
TEMPERATURE STABILITY
TEMPERATURE STABILITY MAXIMUM
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
4
-
Q6Y0Z3
60 days, 50% loss of activity
20
-
Q6Y0Z3
8 days, 50% loss of activity
21
-
-
at room temperature stable for more than 1 month
25
-
-
half-life: more than 2 months
30
35
-
48 h, stability starts to decrease above 30-35C
30
-
Q6Y0Z3
3 days, 50% loss of activity
40
-
-
half-life: 94 min
45
-
Q6Y0Z3
4.5 h, 50% loss of activity
50
-
Q6Y0Z3
2 min, 50% loss of activity
60
-
C5J3R6
retained 28% of activity at 60C
60
-
-
1 h, D-xylose reductase 1, D-xylose reductase 2, complete loss of activity
60
-
A9QVV8
1 h, 80% loss of activity, half-life is around 15 min
additional information
-
-
non-ionic detergents and bovine serum albumin stabilize the enzyme to a significant extent during long-term incubation at 25C, 30C or 38C
GENERAL STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
stable enzyme at 25C in phosphate and Tris buffer of various ionic strengths between pH 6.0 and 7.0
-
OXIDATION STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
the enzyme undergoes thiol oxidation during storage or purification
-
286260
STORAGE STABILITY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
-18C, 4 months, activity in cell extract remains stable
-
38C, 3 h, activity in cell extract remains stable
-
4C, 3 h, activity in cell extract remains stable
-
4C, enzyme retains activity for several months
A0MTG4
-20C, pure enzyme preparation is stable for more than 4 months
-
4C, pure enzyme preparation is stable for more than 4 months
-
4C, stable for several months
-
EXPRESSION
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
the Aspergillus niger transcriptional activator XlnR, which is involved in the degradation of the polysaccharides xylan and cellulose, also regulates D-xylose reductase gene expression
-, Q9P8R5
formation of xylose reductase in the yeast Candida tropicalis is significantly repressed in cells grown on medium that contains glucose as carbon and energy source, because of the repressive effect of glucose
-
formation of xylose reductase in the yeast Candida tropicalis is significantly repressed in cells grown on medium that contains glucose as carbon and energy source, because of the repressive effect of glucose
Candida tropicalis ATCC 20336
-
-
Renatured/COMMENTARY
ORGANISM
UNIPROT ACCESSION NO.
LITERATURE
denaturation buffers of either pH 6.0 or 8.0, containing urea in concentrations of 2, 4, 6, and 8 M, are used and analysed in SDS-PAGE. Optimal solvation of the XylR giving the lowest background of Escherichia coli proteins is performed with 4 M urea at pH 8.0. For renaturation, a set of buffers containing 0, 0.1, 0.5, 1 and 1.5 mM glutathione (red:ox = 1:1) at pH values of 5.0, 6.0, 7.0, and 8.0 are tested. Refolding occurrs at 8C and its progress is analysed by assaying the volumetric activity in the respective buffers. Best renaturation results are obtained in a 20 mM Tris/HCl buffer at pH 7.0 without glutathione. After 4 days about 70% of the activity of the XylR is recovered. Buffers at pH 8.0 work slightly less efficient compared to that of pH 7.0. At pH 5.0 and 6.0 refolding is drastically reduced. Increasing concentrations of glutathione do not improve renaturation
O74237
APPLICATION
ORGANISM
UNIPROT ACCESSION NO.
COMMENTARY
LITERATURE
synthesis
-
dual specific xylose reductase (dsXR) has an about 4fold higher specificity for NADH than NADPH. This fact could make this enzyme an interesting candidate to be used in metabolic engineering of the yeast xylose metabolism, likely in Saccharomyces cerevisiae. Increased levels of dsXR activity could contribute to an improvement of ethanol production from D-xylose by reducing the cofactor imbalance of the initial catabolic pathway
synthesis
O74237
production of xylitol
synthesis
-
fermentation of mixed glucose-xylose substrates in Saccharomyces cerevisiae strains BP10001 and BP000, expressing Candida tenuis xylose reductase in mutated NADH-preferring form and NADPH-preferring wild-type form, respectively. Glucose and xylose, each at 10 g/l, are converted sequentially. The distribution of fermentation products from glucose is identical for both strains whereas when using xylose, BP10001 shows enhanced ethanol yield and decreased yields of xylitol and glycerol as compared to BP000. Increase in xylose concentration from 10 to 50 g/l results in acceleration of substrate uptake by BP10001 and reduction of the xylitol yield. In mixed substrate batches, xylose is taken up at low glucose concentrations and up to 5fold enhanced xylose uptake rate is found towards glucose depletion
synthesis
Candida tenuis CBS 4435
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production of xylitol
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synthesis
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the enzyme is useful for xylitol bioproduction, profiles, overview
synthesis
Meyerozyma guilliermondii FTI, Meyerozyma guilliermondii FTI 20037
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the enzyme is useful for xylitol bioproduction, profiles, overview
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synthesis
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this enzyme is one of the most active xylose reductases and may be used for the in vitro production of xylitol
synthesis
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the cofactor preference of Pichia stipitis xylose reductase is altered by site-directed mutagenesis. When the K270R xylose reductase is combined with a metabolic engineering strategy that ensures high xylose utilization capabilities, a recombinant Saccharomyces cerevisiae strain is created that provides a unique combination of high xylose consumption rate, high ethanol yield and low xylitol yield during ethanolic xylose fermentation
synthesis
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D-xylose is the second most abundant renewable sugar in nature, and its fermentation to ethanol has great economical potential. Unfortunately, Saccharomyces cerevisiae, which has been optimized for ethanol production, cannot utilize xylose efficiently, while D-xylulose, an isomerization product of D-xylose, can be assimilated. A major strategy for constructing xylose-fermenting Saccharomyces cerevisiae is to introduce genes involved in xylose metabolism from other organisms. Xylose reductase and xylitol dehydrogenase (EC 1.1.1.9) from the xylose-fermenting yeast Pichia stipitis are cloned into Saccharomyces cerevisiae to allow xylose fermentation to ethanol. In this case, xylose is converted into xylulose by the sequential actions of two oxidoreductases. First, Pichia stipitis xylose reductase catalyses the reduction of xylose into xylitol with NAD(P)H as co-substrate. Xylitol is then oxidized by PsXDH (Pichia stipitis xylitol dehydrogenase) which uses NAD+ exclusively as co-substrate to yield xylulose. The different coenzyme specificity of the two enzymes xylose reductase and xylitol dehydrogenase, however, creates an intracellular redox imbalance, which results in low ethanol yields and considerable xylitol by-product formation. A mutant is constructed that shows an altered active site that is more unfavorable for NADPH than NADH in terms of both Km and kcat. There are potentials for application of the mutant (K270S/N272P/S271G/R276F) in constructing a more balanced xylose reductase/xylitol dehydrogenase pathway in recombinant xylose-fermenting Saccharomyces cerevisiae strains