• Korean Journal of Microbiology
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• v.32 no.4
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• pp.306-314
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• 1994

The action mode of xylanase II from Trichoderma koningii ATCC 26113 on xylan and related oligosaccharides (xylotriose, xylotetraose, and arabinoxylotriose) indicated that xylanase II is an endo-enzyme and also has trans-xylosidase activity. The $^1HNMR$-NMR studies of the reaction products formed by xylanase II revealed that all the hydrolysis products of xylooligosaccharides by the enzyme have only ${\beta}$-1,4-xylosidic linkage(s). Chemical modification of the enzyme with iodoacetamide showed that two cysteine residues per molecule of the enzyme was essential for the activity. Modification of the enzyme with N-bromosuccinimide demonstrated that four of the eight tryptophan residues were involved in its active site.

• Journal of the Korean Wood Science and Technology
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• v.46 no.6
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• pp.670-680
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• 2018

Acanthophysium sp. KMF001, a wood rotting fungus, produces a strong crude enzyme complex that efficiently produces simple sugars from wood. The transcriptomic analysis of Acanthophysium sp. KMF001 identified 14 genes for putative glycoside hydrolases. Among them, isotig01043 was expressed heterogeneously in Escherichia coli BL21(DE3), and the expressed protein exhibited an endo-${\beta}$-1,4-xylanase activity which showed the optimum reaction at pH 5.0 and $30^{\circ}C$. The enzyme kinetic values of $K_m$ and $V_{max}$ were 25.92 mg/ml and $0.628{\mu}mole/mg/ml$, respectively. The enzymatic characteristics of the expressed xylanase showed a typical fungal xylanase. However, the bioinformatics analysis suggested that the protein encoded by isotig01043 was a novel xylanase based on a low identity when it was compared with the closest protein in the NCBI database and a similar protein domain with GH16_fungal_Lam16A_glucanase, which had not been earlier suggested as a xylanase.

• Mycobiology
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• v.39 no.2
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• pp.121-124
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• 2011

The cDNA of endo-1,$4-{\beta}-xylanaseA$, isolated from Phaenerocheate chrysosporium was expressed in Pichia pastoris. Using either the intrinsic leader peptide of XynA or the ${\alpha}$-factor signal peptide of Saccharomyces cerevisiae, xylanaseA is efficiently secreted into the medium at maximum concentrations of 1,946 U/L and 2,496 U/L, respectively.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.1
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• pp.65-72
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• 2008

Kappa number and brightness were more increased with treatment of endo-xylanase than hydrogen-peroxide. In pulp bleaching process, endo-xylanse was most effective in the other enzyme treatment. Exo-xylanase was effective more than 4 unit treatment. Kappa number was tiny increased with enzyme ratio, but less than 4 unit treatment, increased with hydrogen peroxide treatment ratio. In more than 4 unit acetyl-estease treatment, Kappa number and brightness were not influenced with enzyme treatment ratio, but concentration of hydrogen-peroxide.

• Journal of Microbiology and Biotechnology
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• v.19 no.8
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• pp.823-828
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• 2009

An endo-${\beta}-1$,4-xylanase (${\beta}$-xylanase) from Trichoderma harzianum C4 was purified without cellulase activity by sequential chromatographies. The specific activity of the purified enzyme preparation was 430 units/mg protein on D-xylan. The complementary DNA (cDNA) encoding ${\beta}$-xylanase (xynII) was amplified by PCR and isolated from cDNA PCR libraries constructed from T. harzianum C4. The nucleotide sequence of the cDNA fragment contained an open reading frame of 663 bp that encodes 221 amino acids, of which the mature protein is homologous to several ${\beta}$-xylanases II. An intron of 63 bp was identified in the genomic DNA sequence of xynII. This gene was expressed in Saccharomyces cerevisiae strains under the control of adh1 (alcohol dehydrogenase I) and pgk1 (phosphoglycerate kinase I) promoters in 2 ${\mu}$-based plasmids, which could render recombinants able to secrete ${\beta}$-xylanase into the media.

• Journal of Microbiology and Biotechnology
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• v.6 no.2
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• pp.79-85
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• 1996

By using a T7 expression system, a large amount of Bacillus stearothermophilus endo-xylanase A (XynA) could be produced in Escherichia coli cells. The overproduced enzyme formed inclusion bodies, and so the protein could be more easily purified to homogeneity. The molecular weight of the purified enzyme was estimated to be 22 kDa by SDS-polyacrylamide gel electrophoresis and 43 kDa by Sephacryl S-200 gel filtration, suggesting that the native enzyme was a homodimer. The pI value was determined to be 8.4. The Michaelis constants for birchwood xylan and oat spelts xylan were calculated to be 3.83 mg/ml and 5.03 mg/ml, respectively, and the $V_{max}$ max/ values for both xylans were 2.86 $\mu mole$/min. The purified enzyme was most active at $55^{\circ}C$ and pH 8.0, and stable up to $60^{\circ}C$ and in the near neutral pH range. From the zymogram, Bacillus stearothermophilus was found to have at least three xylanases and the purified one was the smallest among them.

• Journal of Microbiology and Biotechnology
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• v.5 no.3
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• pp.117-124
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• 1995

A gene (xynA) encoding the endo-xylanase (E.C.3.2.1.8) from Bacillus stearothermophilus was cloned in E. coli, and its complete nucleotide sequence was determined. The xynA gene consists of a 636 base pairs open reading frame coding for a protein of 212 amino acids with a deduced molecular weight of 23, 283 Da. A putative signal sequence of 27 amino acid residues shows the features comparable with the Bacillus signal sequences; namely, the signal contains a positively charged region close to the N-terminus followed by a long hydrophobic string. The coding sequence is preceded by a possible ribosome binding site with a free energy value of -16.6 kcal/mol and the transcription initiation signals are located further upstream. The translation termination codon (TAA) at the 3 end of the coding sequence is followed by two palindrome sequences, one of which is thought to act as a terminator. The xynA gene has a high GC content, especially in the wobble position of codons (64%). Comparison of the primary protein sequence with those of other xylanases shows a high homology to the xylanases belonging to family G.

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.255-264
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• 1996

The hydrolysis products formed from birchwood xylan by the action of an alkaline xylanase (CX-III) from alkalophilic Cephaloxporium sp. RYM-202 were xylobiose and xylooligosaccharides polymerized with more than 4 sugar molecules. This enzyme was not active on xylobiose but readily attacked xylotriose accumulating xylobiose as a major product. The predominant end-products from xylotetraose by CX-III were xylobiose and xylotriose. These results indicate that the enzyme is typically endo-type xylanase possessing transglycosidase activity. Chemical modification of CX-III with N-bromosuccinimide revealed that two tryptophan residues per molecule of CX-III were essential for its catalytic activity on xylan. On the other hand, iodoacetamide and diethylpyrocarbonate did not influence the activity of the enzyme, suggesting that cysteine and histidine residues are not involved in the active site of this alkaline xylanase.

• Korean Journal of Microbiology
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• v.31 no.1
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• pp.63-71
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• 1993

A xylanase (xylanase I) was purified 11.9-fold from the culture filtrate of Trichoderma koningii ATCC 26113 by the column chromatography on Sephadex G-75, SP-Sephadex C-50, DEAE-Sephadex A-50 and Sephadex G-50 with an overall yield of 8.2%. The molecular mass determined by gel filtration and sodium dodecyl sulfate polyacrylamide gel electrophoresis was found to be a monomeric polypeptide of ca. 35 kDa. The isoelectric point of the enzyme was estimated to be 9.3. The optimal reaction pH and temperature are 5.8 and 55.deg.C, respectively. The enzyme is stable up to 60.deg.C, while 78% of its activity is lost after the incubation for 10 min at 70.deg.C. The enzyme hydrolyzes sylan with relatively high activity, as well as carboxymethyl cellulose and avicel. The $K_{m}$ values of the enzyme for oat-spelf sylan, larchwood xylan and Avicel were 3.5, 1.6 and 10. 1 mg/ml, respectively. The enzyme hydrolyzed oat-spelt sylan to sylose, sylobiose, sylotriose and arabionoxylobiose, while it degraded larchwood xylan to xylose, xylobiose, xylotriose and arabionoxylobiose, while it degraded larchwood xylan to xylose, xylobiose and xylotriose as the major products. The hydrolysis patterns indicate that xylanase I is endo-enzyme.e.

• Journal of Microbiology and Biotechnology
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• v.24 no.7
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• pp.943-953
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• 2014

The XylH gene (1,167-bp) encoding a novel hemicellulase (41,584 Da) was identified from the genome of Microbacterium trichothecenolyticum HY-17, a gastrointestinal bacterium of Gryllotalpa orientalis. The enzyme consisted of a single catalytic domain, which is 74% identical to that of an endo-${\beta}$-1,4-xylanase (GH10) from Isoptericola variabilis 225. Unlike other endo-${\beta}$-1,4-xylanases from invertebrate-symbiotic bacteria, rXylH was an alkali-tolerant multifunctional enzyme possessing endo-${\beta}$-1,4-xylanase activity together with ${\beta}$-1,3/${\beta}$-1,4-glucanase activity, which exhibited its highest xylanolytic activity at pH 9.0 and 60oC, and was relatively stable within a broad pH range of 5.0-10.0. The susceptibilities of different xylosebased polysaccharides to the XylH were assessed to be as follows: oat spelts xylan > beechwood xylan > birchwood xylan > wheat arabinoxylan. rXylH was also able to readily cleave p-nitrophenyl (pNP) cellobioside and pNP-xylopyranoside, but did not hydrolyze other pNP-sugar derivatives, xylobiose, or hexose-based materials. Enzymatic hydrolysis of birchwood xylan resulted in the product composition of xylobiose (71.2%) and xylotriose (28.8%) as end products.