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1.
A laccase has been purified from the liquid culture growth medium containing bagasse particles of Fomes durissimus. The method involved concentration of the culture filtrate by ultrafiltration and anion exchange chromatography on diethyl
aminoethyl cellulose. The sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE) and native polyacrylamide
gel electrophoresis both gave single protein band indicating that the enzyme preparation was pure. The molecular mass of the
purified laccase determined from SDS-PAGE analysis was 75 kDa. Using 2,6-dimethoxyphenol as the substrate, the determined
K
m and k
cat values of the laccase are 182 μM and 0.35 s−1, respectively, giving a k
cat/K
m value of 1.92 × 103 M−1 s−1. The pH and temperature optimum were 4.0 and 35 °C, respectively. The purified laccase has yellow colour and does not show
absorption band around 610 nm found in blue laccases. Moreover, it transformed methylbenzene to benzaldehyde in the absence
of mediator molecules, property exhibited by yellow laccases. 相似文献
2.
Yun Wang Jin-Zhu Song Qian Yang Zhi-Hua Liu Xiao-Mei Huang Yan Chen 《Applied biochemistry and biotechnology》2010,162(3):843-854
A gene encoding chitin deacetylase was cloned by polymerase chain reaction from Aspergillus nidulans. Sequencing result showed 40% homology to the corresponding gene from Colletotrichum lindemuthianum. The complete gene contains an open reading frame of 747 nucleotides encoding a sequence of 249 amino acid residues. The
chitin deacetylase gene was subcloned into a pET28a expression vector and expressed in Escherichia coli BL21 and then purified by metal affinity chromatography using a His-bind column. The purified chitin deacetylase demonstrated
an activity of 0.77 U ml−1 for the glycol chitin substrates, and its specific activity was 4.17 U mg−1 for it. The optimal temperature and pH of the purified enzyme were 50 °C and 8.0, respectively. When glycol chitin was used
as the substrate, K
m was 4.92 mg ml−1, and K
cat showed 6.25 s−1, thus the ratio of K
cat and K
m was 1.27 ml s−1 mg−1. The activity of chitin deacetylase was affected by a range of metal ions and ethylenediaminetetraacetic acid. 相似文献
3.
S. Subramaniyan 《Applied biochemistry and biotechnology》2012,166(7):1831-1842
Low molecular weight endo-xylanase from Bacillus pumilus SSP-34 was purified to homogeneity using ion exchange and size exclusion chromatographies. Xylanases were isolated by novel
purification protocol which includes the use of anion exchange matrix such as DEAE Sepharose CL 6B with less affinity towards
enzyme protein. The purified B. pumilus SSP-34 have a molecular weight of 20 kDa, with optimum pH and temperature at 6.0 and 50 °C, respectively. The enzyme was
stable at 50 °C for 30 min. It showed remarkable stability at pH values ranging from 4.5 to 9 when the reaction was carried
out at 50 °C. K
m and V
max values, determined with oats spelts xylan were 6.5 mg ml−1 and 1,233 μmol min−1 mg−1 protein, respectively, and the specific activity was 1,723 U mg−1 相似文献
4.
Vivekanand V Dwivedi P Pareek N Singh RP 《Applied biochemistry and biotechnology》2011,165(1):204-220
In solid-state fermentation, among various solid supports evaluated, banana peel was found to be an ideal support and resulted
into higher levels of laccase (6281.4 ± 63.60 U l−1) along with notable levels of manganese peroxidase production (1339.0 ± 131.23 U l−1) by Aspergillus fumigatus VkJ2.4.5. Maximum levels of laccase was achieved under derived conditions consisting of 80% of moisture level, 6 days of
incubation period, 6% inoculum level, and an aeration level of 2.5 l min−1. A column-tray bioreactor was designed to scale up and economize the enzyme production in three successive cycles of fermentation
using the same fungal biomass. Thermal and pH stability profiles revealed that enzyme was stable up to 50°C and at varying
pH range from 5–9 for up to 2 h. The apparent molecular weight of laccase was found to be 34 ± 1 kDa. MALDI-TOF/TOF analysis
of the protein showed significant homology with maximum identity of 67% to other laccases reported in database. 相似文献
5.
A 66-kDa thermostable family 1 Glycosyl Hydrolase (GH1) enzyme with β-glucosidase and β-galactosidase activities was purified
to homogeneity from the seeds of Putranjiva roxburghii belonging to Euphorbiaceae family. N-terminal and partial internal amino acid sequences showed significant resemblance to plant GH1 enzymes. Kinetic
studies showed that enzyme hydrolyzed p-nitrophenyl β-d-glucopyranoside (pNP-Glc) with higher efficiency (K
cat/K
m = 2.27 × 104 M−1 s−1) as compared to p-nitrophenyl β-d-galactopyranoside (pNP-Gal; K
cat/K
m = 1.15 × 104 M−1 s−1). The optimum pH for β-galactosidase activity was 4.8 and 4.4 in citrate phosphate and acetate buffers respectively, while
for β-glucosidase it was 4.6 in both buffers. The activation energy was found to be 10.6 kcal/mol in the temperature range
30–65 °C. The enzyme showed maximum activity at 65 °C with half life of ~40 min and first-order rate constant of 0.0172 min−1. Far-UV CD spectra of enzyme exhibited α, β pattern at room temperature at pH 8.0. This thermostable enzyme with dual specificity
and higher catalytic efficiency can be utilized for different commercial applications. 相似文献
6.
Javed MR Rashid MH Nadeem H Riaz M Perveen R 《Applied biochemistry and biotechnology》2009,157(3):483-497
Monomeric extracellular endoglucanase (25 kDa) of transgenic koji (Aspergillus oryzae cmc-1) produced under submerged growth condition (7.5 U mg−1 protein) was purified to homogeneity level by ammonium sulfate precipitation and various column chromatography on fast protein
liquid chromatography system. Activation energy for carboxymethylcellulose (CMC) hydrolysis was 3.32 kJ mol−1 at optimum temperature (55 °C), and its temperature quotient (Q
10) was 1.0. The enzyme was stable over a pH range of 4.1–5.3 and gave maximum activity at pH 4.4. V
max for CMC hydrolysis was 854 U mg−1 protein and K
m was 20 mg CMC ml−1. The turnover (k
cat) was 356 s−1. The pK
a1 and pK
a2 of ionisable groups of active site controlling V
max were 3.9 and 6.25, respectively. Thermodynamic parameters for CMC hydrolysis were as follows: ΔH* = 0.59 kJ mol−1, ΔG* = 64.57 kJ mol−1 and ΔS* = −195.05 J mol−1 K−1, respectively. Activation energy for irreversible inactivation ‘E
a(d)’ of the endoglucanase was 378 kJ mol−1, whereas enthalpy (ΔH*), Gibbs free energy (ΔG*) and entropy (ΔS*) of activation at 44 °C were 375.36 kJ mol−1, 111.36 kJ mol−1 and 833.06 J mol−1 K−1, respectively. 相似文献
7.
An exoinulinase has been isolated, purified and characterised from a commercially available broth of Aspergillus ficuum. The enzyme was purified 4.2-fold in a 21% yield with a specific activity of 12,300 U mg−1(protein) after dialysis, ammonium sulphate fractionation and Sephacryl S-200 size exclusion and ion exchange chromatography.
The molecular weight of this enzyme was estimated to be 63 kDa by SDS-PAGE. It exhibited a pH and temperature optima of 5.4
and 50 °C respectively and under such conditions the enzyme remained stable with 96% and 63.8% residual activity after incubation
for 12 h and 72 h respectively. The respective K
m and V
max values were 4.75 mM and 833.3 μmol min−1 ml−1, respectively. Response surface methodological statistical analysis was evaluated for the maximal production of fructose
from the hydrolysis of pure commercial chicory inulin. Incubation of the dialyzed crude exoinulinase (100 U/ml, 48 h, 50 °C,
150% inulin, pH 5.0) produced the highest amount of fructose (106.4 mg/ml) under static batch conditions. The purified exoinulinase
was evaluated for fructose production and the highest amount (98 mg/ml) was produced after 12 h incubation at 50 °C, 150%
inulin pH 5.0. The use of a crude exoinulinase preparation is economically desirable and the industrial production of fructose
from inulin hydrolysis is biotechnologically feasible. 相似文献
8.
Donata Iandolo Alessandra Piscitelli Giovanni Sannia Vincenza Faraco 《Applied biochemistry and biotechnology》2011,163(1):40-51
A process of solid state fermentation (SSF) on tomato pomace was developed with the white-rot fungi Pleurotus ostreatus and Trametes versicolor, using sorghum stalks as support. Operative parameters (humidity, water activity, and size of substrate particles) guaranteeing
a good colonization of tomato pomace by both fungi were defined and conditions for production at high titers of the industrially
relevant enzymes laccase, xylanase and protease were identified. Significant laccase activity levels (up to 36 U g−1 dry matter) were achieved without any optimization of culture conditions, neither by nutrient addition nor by O2 enrichment. Furthermore, protease activity levels up to 34,000 U g−1 dry matter were achieved, being higher than those reported for the fungi typically considered as the best protease producers
such as Aspergillus strains. Moreover, as one of the most significant results of this study, analysis of P. ostreatus tomato SSF samples by zymogram revealed two bands with laccase activity which had not been detected so far. 相似文献
9.
Thin nylon-SiO2 membranes made by sol–gel SiO2 coating of a nylon weaving were impregnated in a second step with an aqueous carbonic anhydrase solution. The biocatalytic
hybrid membranes obtained were applied to the capture of CO2 from a N2–CO2 gas mixture containing 10% CO2, under a total pressure ≈ 1 atm. The CO2 permeance of these membranes was at least similar to those previously reported for liquid membranes. When impregnated with
a 0.2 mg mL−1 enzyme solution in a pH ≈ 8 NaHCO3 buffer, the permeance of a nylon-SiO2 membrane was multiplied by a factor ≈ 3 when the buffer molarity was increased from 0.1 to 1 M. By comparison, this permeance
only increased by a factor ≈ 1.3 without any enzyme in the same buffers. The permeance was also higher with the enzyme than
without it: respectively ≈3.7 10−8 and ≈4.7 10−9 mol
\textm\textmembrane - 2 {\text{m}}_{\text{membrane}}^{{^{ - 2} }} s−1 Pa−1 with and without enzyme, in a 1 M NaHCO3 buffer. A maximum permeance was observed for an enzyme concentration of ≈0.2 mg mL−1, possibly due to a competition between the H+ ions produced from CO2,aq by the enzyme and the H+ captured by the buffer. Besides, when the SiO2–CO2 contact was enhanced by the membrane architecture, SiO2 improved the CO2 permeance. The influence of an in situ CaCO3 deposit was also investigated and it improved the CO2 permeance when no enzyme was added. 相似文献
10.
A heparinase-producing fungus was isolated, and the strain was taxonomically characterized as Aspergillus flavus by morphophysiological and 26S rRNA gene homology studies. The culture produced intracellular heparinase enzyme, which was
purified 40.5-fold by DEAE-Sephadex A-50, CM-Sephadex C-50, and Sephadex G-100 column chromatography. Specific activity of
the purified enzyme was found to be 44.6 IU/μg protein and the molecular weight of native as well as reduced heparinase was
24 kDa, showing a monomeric unit structure. Peptide mass spectrum showed poor homogeneity with the database in the peptide
bank. The enzyme activity was maximum at 30 °C in the presence of 300 mM NaCl at pH 7.0. In the presence of Co2+, Mn2+ ions, and reducing agents (β-mercaptoethanol, dithiothreitol), enzyme activity was enhanced and inhibited by iodoacetic acid.
These observations suggested that free sulfohydryl groups of cysteine residues were necessary for catalytic activity of the
enzyme. The enzyme was also inhibited by histidine modifier, DEPC, which suggests that along with cysteine, histidine may
be present at its active site. The enzyme showed a high affinity for heparin as a substrate with K
m and V
max as 2.2 × 10−5 M and 30.8 mM min−1, respectively. The affinity of the enzyme for different glycosaminoglycans studied varied, with high substrate specificity
toward heparin and heparin-derived polysaccharides. Depolymerization of heparin and fractionation of the oligosaccharides
yielded heparin disaccharides as main product. 相似文献
11.
Dengeti Shrinivas Gunashekaran Savitha Kumar Raviranjan Gajanan Ramchandra Naik 《Applied biochemistry and biotechnology》2010,162(7):2049-2057
A highly thermostable alkaline xylanase was purified to homogeneity from culture supernatant of Bacillus sp. JB 99 using DEAE-Sepharose and Sephadex G-100 gel filtration with 25.7-fold increase in activity and 43.5% recovery.
The molecular weight of the purified xylanase was found to be 20 kDA by SDS-PAGE and zymogram analysis. The enzyme was optimally
active at 70 °C, pH 8.0 and stable over pH range of 6.0–10.0.The relative activity at 9.0 and 10.0 were 90% and 85% of that
of pH 8.0, respectively. The enzyme showed high thermal stability at 60 °C with 95% of its activity after 5 h. The K
m and V
max of enzyme for oat spelt xylan were 4.8 mg/ml and 218.6 μM min−1 mg−1, respectively. Analysis of N-terminal amino acid sequence revealed that the xylanase belongs to glycosyl hydrolase family
11 from thermoalkalophilic Bacillus sp. with basic pI. Substrate specificity showed a high activity on xylan-containing substrate and cellulase-free nature. The hydrolyzed product
pattern of oat spelt xylan on thin-layer chromatography suggested xylanase as an endoxylanase. Due to these properties, xylanase
from Bacillus sp. JB 99 was found to be highly compatible for paper and pulp industry. 相似文献
12.
This study presents the biodecolorization potential of basidiomycete fungi Trametes hirsuta, Pycnoporus sp., and Irpex sp. for different reactive dyes viz. Reactive Red 120, Remazol Brilliant Blue R (RBBR), Reactive Orange G, and Reactive Orange
16 under static and shaking conditions. The screening trials revealed that T. hirsuta exhibited maximum potential (83.75 %) for biodecolorization of RBBR dye under static conditions after the fifth day of incubation.
However, the rate of biodecolorization of RBBR dye by Pycnoporus sp. was much slow and reached maximum (81.25 %) after 15 days of incubation under shaking conditions. By process optimization,
enhanced decolorization (91.2 %) of RBBR by T. hirsuta was achieved at pH 5.5 within 24 h using a defined salt medium amended with p-coumaric acid under static conditions. pH was found to be an important parameter for the enzymatic system involved in RBBR
dye decolorization by T. hirsuta and Pycnoporus sp. Biodecolorization of RBBR dye was determined by a reduction in optical density at the wavelength of maximum absorbance
(λ, 578 nm) by UV–vis spectrophotometer. The shift in maximum wavelength toward shorter/longer wavelength in UV–vis scanning
spectrum revealed the degradation of RBBR dye into different transformation products. 相似文献
13.
A novel laccase producing Basidiomycete Peniophora sp. (NFCCI-2131) was isolated from pulp and paper mill effluent. The optimal temperature and initial pH for laccase production
by the isolate in submerged culture were found to be 30 and 4.6° C, respectively. Maltose (20 g l−1) and tryptone (1.0 g l−1) were the most suitable carbon and nitrogen sources for laccase production. Cu2+ (1.0 mM) and veratryl alcohol induced maximum laccase production giving 6.6 and 6.07 U/ml laccase activity, respectively.
Under optimised culture conditions, 7.6 U/ml activity was obtained, which was 2.4 times higher than that was achieved in basal
medium. An evaluation of the delignification efficiency of the crude enzyme in the presence of redox mediators [2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonic
acid) and (1-hydroxybenzotriazole)] revealed structural changes in lignin and existence of many active centres for both chemical
and biological degradation of lignin following enzymatic treatment. 相似文献
14.
Qiong Liu Peilong Yang Huiying Luo Pengjun Shi Huoqing Huang Kun Meng Bin Yao 《Applied biochemistry and biotechnology》2012,166(6):1442-1453
An endo-β-1,4-mannanase encoding gene, man5, was cloned from Bispora antennata CBS 126.38, which was isolated from a beech stump. The cDNA of man5 consists of 1,299 base pairs and encodes a 432-amino-acid protein with a theoretical molecular mass of 46.6 kDa. Deduced
MAN5 exhibited the highest amino acid sequence identity of 58% to a β-mannanase of glycoside hydrolase family 5 from Aspergillus aculeatus. Recombinant MAN5 was expressed in Pichia pastoris and purified to electrophoretic homogeneity. The specific activity of the final preparation towards locust bean gum was 289
U mg−1. MAN5 showed optimal activity at pH 6.0 and 70 °C and had good adaptation and stability over a broad range of pH values.
The enzyme showed more than 60% of peak activity at pH 3.0–8.0 and retained more than 80% of activity after incubation at
37 °C for 1 h in both acid and alkaline conditions (pH 4.0–11.0). The K
m and V
max values were 1.33 mg ml−1 and 444 μmol min−1 mg−1 and 1.17 mg ml−1 and 196 μmol min−1 mg−1 for locust bean gum and konjac flour, respectively. Of all tested metal ions and chemical reagents, Co2+, Ni2+, and β-mercaptoethanol enhanced the enzyme activity at 1 mM, whereas other chemicals had no effect on or partially inhibited
the enzyme activity. MAN5 was highly resistant to acidic and neutral proteases (trypsin, α-chymotrypsin, collagenase, subtilisin
A, and proteinase K). By virtue of the favorable properties of MAN5, it is possible to apply this enzyme in the paper and
food industries. 相似文献
15.
Xiaolin Pei Qiuyan Wang Xiaofeng Qiu Longbin Ying Junhua Tao Tian Xie 《Applied biochemistry and biotechnology》2010,162(5):1423-1434
2-Deoxyribose-5-phosphate aldolase (DERA) catalyzes a sequential aldol reaction useful in synthetic chemistry. In this work,
the effect of a feeding strategy on the production of a thermophilic DERA was investigated in fed-batch cultures of recombinant
Escherichia coli BL21 (pET303-DERA008). The predetermined specific growth rate (μ
set) was evaluated at 0.20, 0.15, and 0.10 h−1, respectively. The DERA concentration and volumetric productivity were associated with μ
set. The cells synthesized the enzyme most efficiently at μ
set = 0.15 h−1. The maximum enzyme concentration (5.12 g/L) and total volumetric productivity (0.256 g L−1 h−1) obtained were over 10 and five times higher than that from traditional batch cultures. Furthermore, the acetate concentration
remained at a relatively low level, less than 0.4 g/L, under this condition which would not inhibit cell growth and target
protein expression. Thus, a specific growth rate control strategy has been successfully applied to induce fed-batch cultures
for the maximal production of the thermophilic 2-deoxyribose-5-phosphate aldolase. 相似文献
16.
Junpei Zhou Huoqing Huang Kun Meng Pengjun Shi Yaru Wang Huiying Luo Peilong Yang Yingguo Bai Bin Yao 《Applied biochemistry and biotechnology》2010,160(5):1277-1292
A bacterial strain, Streptomyces sp. TN119, was isolated from the gut of Batocera horsfieldi larvae and showed xylanolytic activity. A degenerate primer set was designed based on the base usage of G and C in Actinobacteria xylanase-coding sequences belonging to the glycosyl hydrolases family 10 (GH 10), and used to clone the partial xylanase
gene from Streptomyces sp. TN119. A modified thermal asymmetric interlaced (TAIL)-PCR specific for high-GC genes, named GC TAIL-PCR, was developed
to obtain the full-length xylanase gene (xynA119; 1089 bp). Rich in GC content (67.8%), xynA119 encodes a new GH 10 xylanase (XynA119), which shares highest identity (48.8%) with an endo-1,4-β-xylanase from Cellulosimicrobium sp. HY-12. Recombinant XynA119 was expressed in Escherichia coli BL21 (DE3) and purified to electrophoretic homogeneity. The enzyme showed maximal activity at pH 6.5 and 60 °C, was stable
at pH 4.0 to 10.0 and 50 °C, was resistant to most chemicals (except for Cu2+, Mn2+, Ag+, Hg2+ and SDS) and trypsin, and produced simple products. The specific activity, K
m, V
max, and k
cat using oat-spelt xylan as substrate were 57.9 U mg−1, 1.0 mg ml−1, 74.8 μmol min−1 mg−1, and 49.2 s–1, respectively. 相似文献
17.
Glucose 2-oxidase (pyranose oxidase, pyranose:oxygen-2-oxidoreductase, EC 1.1.3.10) from Coriolus versicolor catalyses the oxidation of d-glucose at carbon 2 in the presence of molecular O2 producing d-glucosone (2-keto-glucose and d-arabino-2-hexosulose) and H2O2. It was used to convert d-glucose into d-glucosone at moderate pressures (i.e. up to 150 bar) with compressed air in a modified commercial batch reactor. Several
parameters affecting biocatalysis at moderate pressures were investigated as follows: pressure, [enzyme], [glucose], pH, temperature,
nature of fluid and the presence of catalase. Glucose 2-oxidase was purified by immobilized metal affinity chromatography
on epoxy-activated Sepharose 6B-IDA-Cu(II) column at pH 6.0. The rate of bioconversion of d-glucose increased with the pressure since an increase in the pressure with compressed air resulted in higher rates of conversion.
On the other hand, the presence of catalase increased the rate of reaction which strongly suggests that H2O2 acted as inhibitor for this reaction. The rate of bioconversion of d-glucose by glucose 2-oxidase in the presence of either nitrogen or supercritical CO2 at 110 bar was very low compared with the use of compressed air at the same pressure. The optimum temperature (55°C) and
pH (5.0) of d-glucose bioconversion as well as kinetic parameters for this enzyme were determined under moderate pressure. The activation
energy (E
a) was 32.08 kJ mol−1 and kinetic parameters (V
max, K
m, K
cat and K
cat/K
m) for this bioconversion were 8.8 U mg−1 protein, 2.95 mM, 30.81 s−1 and 10,444.06 s−1 M−1, respectively. The biomass of C. versicolor as well as the cell-free extract containing glucose 2-oxidase activity were also useful for bioconversion of d-glucose at moderate pressures. The enzyme was apparently stable at moderate pressures since such pressures did not affect
significantly the enzyme activity. 相似文献
18.
Yao Guo Fengxia Lu Haizhen Zhao Yanchong Tang Zhaoxin Lu 《Applied biochemistry and biotechnology》2010,162(2):498-509
A gene of glucose oxidase (GOD) from Aspergillus niger Z-25 was cloned and sequenced. The entire open reading frame (ORF) consisted of 1,818 bp and encoded a putative peptide of
605 amino acids. The gene was fused to the pPICZαA plasmid and overexpressed in Pichia pastoris SMD1168. The recombinant GOD (rGOD) was secreted into the culture using MF-α factor signal peptide under the control of the
AOX1 promoter. Sodium dodecyl sulfate polyacrylamide gel electrophoresis indicated that rGOD exhibited a single band at around
94 kDa. The maximal GOD activity of approximately 40 U/mL was achieved in shake flask by induction under optimal conditions
after 7 days. rGOD was purified by ammonium sulfate precipitate leading to a final specific activity of 153.46 U/mg. The optimum
temperature and pH of the purified enzyme were 40 °C and 6.0, respectively. Over 88% of maximum activity was maintained below
40 °C. And the recombinant enzyme displayed a favorable stability in the pH range from 4.0 to 8.0. The Lineweaver–Burk plotting
revealed that rGOD exhibited a K
m value of 16.95 mM and a K
cat value of 484.26 s−1. 相似文献
19.
Taibi Z Saoudi B Boudelaa M Trigui H Belghith H Gargouri A Ladjama A 《Applied biochemistry and biotechnology》2012,166(3):663-679
An extracellular thermostable xylanase from a newly isolated thermophilic Actinomadura sp. strain Cpt20 was purified and characterized. Based on matrix-assisted laser desorption–ionization time-of-flight mass
spectrometry analysis, the purified enzyme is a monomer with a molecular mass of 20,110.13 Da. The 19 residue N-terminal sequence
of the enzyme showed 84% homology with those of actinomycete endoxylanases. The optimum pH and temperature values for xylanase
activity were pH 10 and 80 °C, respectively. This xylanase was stable within a pH range of 5–10 and up to a temperature of
90 °C. It showed high thermostability at 60 °C for 5 days and half-life times at 90 °C and 100 °C were 2 and 1 h, respectively.
The xylanase was specific for xylans, showing higher specific activity on soluble oat-spelt xylan followed by beechwood xylan.
This enzyme obeyed the Michaelis–Menten kinetics, with the K
m and k
cat values being 1.55 mg soluble oat-spelt xylan/ml and 388 min−1, respectively. While the xylanase from Actinomadura sp. Cpt20 was activated by Mn2+, Ca2+, and Cu2+, it was, strongly inhibited by Hg2+, Zn2+, and Ba2+. These properties make this enzyme a potential candidate for future use in biotechnological applications particularly in
the pulp and paper industry. 相似文献
20.
Wanli Liu Pengjun Shi Qiang Chen Peilong Yang Guozeng Wang Yaru Wang Huiying Luo Bin Yao 《Applied biochemistry and biotechnology》2010,162(1):1-12
A xylanase-encoding gene, xyn11F63, was isolated from Penicillium sp. F63 CGMCC1669 using degenerated polymerase chain reaction (PCR) and thermal asymmetric interlaced (TAIL)-PCR techniques.
The full-length chromosomal gene consists of 724 bp, including a 73-bp intron, and encodes a 217 amino acid polypeptide. The
deduced amino acid sequence of xyn11F63 shows the highest identity of 70% to the xylanase from Penicillium sp. strain 40, which belongs to glycosyl hydrolases family 11. The gene was overexpressed in Pichia pastoris, and its activity in the culture medium reached 516 U ml−1. After purification to electrophoretic homogeneity, the enzyme showed maximal activity at pH 4.5 and 40°C, was stable at
acidic buffers of pH 4.5–9.0, and was resistant to proteases (proteinase K, trypsin, subtilisin A, and α-chymotrypsin). The
specific activity, K
m, and V
max for oat spelt xylan substrate was 7,988 U mg−1, 22.2 mg ml−1, and 15,105.7 μmol min−1 mg−1, respectively. These properties make XYN11F63 a potential economical candidate for use in feed and food industrial applications. 相似文献