• Korean Journal of Pharmacognosy
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• v.38 no.3 s.150
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• pp.291-295
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• 2007

Eight compounds were isolated from the whole plants of Euphorbia supina (Euphorbiaceae) through repeated silica gel, YMC gel and Sephadex LH-20 column chromatography. Their chemical structures were elucidated as 7-hydroxy-6-methoxycoumarin (scopoletin) (1), p-hydroxybenzaldehyde (2), methyl gallate (3), gallic acid (4), quercetin (5), quercetin $3-O-{\alpha}-L-arabinofuranoside$ (avicularin) (6), kaempferol $3-O-{\alpha}-L-arabinofuranoside$ (juglanin) (7) and kaempferol $3-O-{\beta}-D-glucopyranoside$ (astragaline) (8) by spectroscopic (NMR and MS) analysis.

• The Korean Journal of Food And Nutrition
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• v.14 no.1
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• pp.65-68
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• 2001

${\alpha}$-L-Arabinofuranosidase was purified from the culture supernatant of Bacillus sp. DSNC 101. The enzyme had a molecular weight of 56 kDa. Optimum temperature and pH for ${\alpha}$-L-arabinofuranosidase activity were 55$^{\circ}C$ and 7.0 respectively. The Michaelis constant(Km) and maximal reaction velo-city(Vmax) for p-nitrophenyl-${\alpha}$-L-arabinofuranoside were 1.0 mM and 113.6 U/mg protein, respe-ctively. ${\alpha}$-L-Arabinofuranosidase was completely inhibited by HgCl$_2$ and CuSO$_4$. The enzyme was spe-cific for the ${\alpha}$-linked arabinoside in the furanoside configuration. The enzyme was produced during growth on agricultural residue such as rice straw, but not during growth on spelt xylan, glucose or cellobiose.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.193.1-193.1
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• 2003

Activity-guided separation for the aerial parts of Rodgersia podophylla A. Gray gave a new acylated flavonoid, quercetin 3-O-${\alpha}$-L-(5$^2$-acetyl)-arabinofuranoside (1), together with six known flavonoids (2-7). Their hepatoprotective activities were determined by using the primary cultures of rat hepatocytes injured by H$_2$O$_2$. Quercetin 3-O-${\alpha}$-L-(3$^2$-acetyl)-arabinofuranoside (3), kaempferol 3-O-${\alpha}$-L-rhamnopyranoside (5) and quercetin 3-O-${\alpha}$-L-rhamnopyranoside (6) exhibited hepatoprotective activities comparable to silybin at the concentration of 50 mM (45.7, 50.8 and 57.3 %, respectively), and the new flavonoid 1 showed hepatoprotective activity at the concentration of 100mM (50.1%).

• Microbiology and Biotechnology Letters
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• v.22 no.6
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• pp.607-613
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• 1994

The Bacillus stearothermophilus arfI gene encoding a-arabinofuranosidase was isolated from the genomic library, cloned into pBR322, and subsequently transferred into the Escherichia coli HB101. The recombinant E. coli was selected from approximately 10,000 transformants screened by making use of its ability to produce a yellow pigment around the colony on the selective medium supplemented with p-nitrophenyl-$\alpha$-L-arabinofuranoside (pNPAf), a chromogenic substrate. The functional clone was found to harbor a recombinant plasmid, pKMG11 with an insertion of about 5 kb derived from the B. stearothermophilus chromosomal DNA. Identity of the arfI gene on the insert DNA was confirmed by a zymogram with 4-methylumbelliferyl-$\alpha$-L-arabinofuranoside as the enzyme substrate. The $\alpha$-arabinofuranosidase from the recombinant E. coli strain showed very high substrate specificity; the enzyme displayed high activity only with pNPAf among many other p- or $o$-nitrophenyl derivatives of several sugars, and acted only on arabinoxylan among various natural arabinose containing polysaccharides tested.

• Journal of Applied Biological Chemistry
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• v.48 no.1
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• pp.7-10
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• 2005

Trichoderma sp. SY most effectively produces an extracellular ${\gamma}$-L-arabinofuranosidase (AF) using arabinose as a carbon source. AF grown on cellulose as a carbon source was purified 28-fold with 4.4% yield by DEAE exchange and HQ/20 cation exchange chromatographies The purified enzyme was found to be homogeneous on SDS-PAGE with molecular weight of 89 kDa. It exhibited a high level of activity with p-nitrophenyl ${\alpha}$-L-arabinofuranoside, showing $K_m$ and $V_{max}$ values of $0.15\;{\mu}M$ and $239.85U{\cdot}mg^{-1}$, respectively and did not require any metal ion for activity. It also released p-nitrophenol from p-nitrophenol conjugated ${\beta}$-D-xylopyranoside, and ${\beta}$-D-galactopyranoside not from ${\beta}$-D-glucopyranoside.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.331-335
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• 1996

The second $\beta$-Xylosidase gene (xylB) from Bacillus stearothermophilus was isolated from the genomic library, cloned into pBR322, and subsequently transferred into Escherichia coli HB101. Six out of 10, 000 transformants were selected from the selective LB medium supplemented with p-nitrophenyl-$\alpha$-L-arabinofuranoside (pNPAf) and ampicillin ($50\mu g$/ml) based on their ability to form a yellow ring around the colony. One of the clones was found to harbor the recombinant plasmid with 5.0 kb foreign DNA, which was identical to the $\alpha$-L-arabinofuranosidase gene (arfI) previously cloned in this lab, while the other five had 3.5 kb of the foreign DNA. Southern blotting experiments confirmed that the 3.5 kb insert DNA was from B. stearothermophilus chromosomal DNA. A zymogram with 4-methylumbelliferyl-$\alpha$-L-arabinofuranoside as the enzyme substrate revealed that the cloned gene product was one of the mutiple $\alpha$-L-arabinofuranosidases produced by B. stearothermophilus. Unlike the arfI gene product, the product of the gene on the insert DNA (xylB) showed an activity not only on pNPAf but also on oNPX suggesting that the cloned gene product could be a bifunctional enzyme having both $\alpha$-L-arabinofuranosidase and $\beta$-xylosidase activities.

• Natural Product Sciences
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• v.17 no.4
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• pp.279-284
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• 2011

Phytochemical studies on the whole extract of Sedum hybridum L., a Mongolian medicinal plant, has been undertaken to isolate active principles responsible for its anti-oxidative and antibacterial activities. Eighteen known compounds, i.e. (1) quercetin, (2) kaempferol, (3) herbacetin-8-O-${\beta}$-D-xylopyranoside, (4) myricetin, (5) gossypetin-8-O-${\beta}$-D-xylopyranoside, (6) gallic acid, (7) 2,4,6-tri-O-galloyl-D-glucopyranose, (8) 6-O-galloylarbutin, (9) myricetin-3-O-${\alpha}$-L-arabinofuranoside, (10) quercetin-3-O-${\alpha}$-L-arabinofuranoside, (11) caffeic acid, (12) ethylgallate, (13) (-) epigallocatechin-3-O-gallate, (14) palmitic acid, (15) stearic acid, (16) stearic acid ethyl ether, (17) ${\beta}$-sitosterol and (18) ${\beta}$-sitosteryl-O-${\beta}$-D-glucopyranose have been isolated and their molecular structures identified by spectroscopic analysis. Thirteen substances including seven flavonol components (1, 2, 3, 4, 5, 9 and 10), five gallic acid derivatives (6, 7, 8, 12 and 13) and caffeic acid (11) exhibited significant, dose-dependent, DPPH radical scavenging activity. Galloyl esters 12 and 13 were revealed to be main active principles for the antibacterial property of the extract of Sedum hybridum L.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.236-244
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• 2014

The gene encoding ${\alpha}-\small{L}$-arabinofuranosidase (AFase) from Paenibacillus sp. DG-22 was cloned, sequenced, and expressed in Escherichia coli. The AFase gene (abfA) comprises a 1,509 bp open reading frame encoding 502 amino acids with a molecular mass of 56,520 daltons. The deduced amino acid sequence of the gene shows that AbfA is an enzyme consisting of only a catalytic domain, and that the enzyme has significant similarity to AFases classified into the family 51 of the glycosyl hydrolases. abfA was subcloned into the pQE60 expression vector to fuse it with a six-histidine tag and the recombinant AFase (rAbfA) was purified to homogeneity. The specific activity of the recombinant enzyme was 96.7 U/mg protein. Determination of the apparent molecular mass by gel-filtration chromatography indicated that AbfA has a tetrameric structure. The optimal pH and temperature of the enzyme were 6.0 and $60^{\circ}C$, respectively. The enzyme activity was completely inhibited by 1 mM $HgCl_2$. rAbfA was active only towards p-nitrophephenyl ${\alpha}-\small{L}$-arabinofuranoside and exhibited $K_m$ and $V_{max}$ values of 3.5 mM and 306.1 U/mg, respectively. rAbfA showed a synergistic effect in combination with endoxylanase on the degradation of oat spelt xylan and wheat arabinoxylan.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2004.06a
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• pp.273-277
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• 2004

$\alpha$-L-Arabinofuranosidase ($\alpha$-L-AFase, EC 3.2.1.55) was isolated from hyperthermophilic microorganism, Thermotoga maritima. The open reading frame (ORF) of $\alpha$-L-AFase gene is 1,455 bp long and encodes 484 amino acid residues with a molecular weight of 55,265 Da. The ORF of $\alpha$-L-AFase gene was introduced into the E. coli expression vector, $_p/RSET-B, and overexpressed in E. coli BL21. The purified recombinant $\alpha$-L-AFase showed the highest activity at 10$0^{\circ}C$ and pH 5.5. The purified enzyme appeared to have no metal cofactor requirement. The Km and specific activity values of the recombinant enzyme were 0.99 mM and 1,200 U/mg on p-nitrophenyl-$\alpha$-L-arabinofuranoside. It released only L-arabinose from sugar beet arabinan, sugar beet debranched arabinan and oat spelts arabinoxylan but had no activity onarabinogalactan and gum arabic. This result suggests that L-arabinose could be produced from natural polysaccharides using this enzyme. Mutant enzymes which Glu26, Glu172 and Glu281 residues were replaced to alanine, aspartic acid or glutamine caused Kcat to decrease by a factor of between 10$^3$ and 10$^4$. Glu172 and Glu281 residues of $\alpha$-L-AFase are seemed to be the acid/base and nucleophile in catalytic reaction, respectively, and Glu26 is supposed to playa key role in substrate binding.ng.

• Korean Journal of Pharmacognosy
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• v.38 no.1
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• pp.76-83
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• 2007

In this study, three triterpenoids, two steroids and nine flavonoids were isolated from the leaves of Alnus firma Sieb. et Zucc. On the basis of spectroscopic evidences, the structures of these compounds were established as ${\beta}$-amyrin acetate, ${\beta}$-amyrin, ${\beta}$-sitosterol, alnustic acid methyl ester, ${\beta}$-sitosterol glucoside, pinocembrin, alnustinol, quercetin, quercetin-3-O-${\alpha}$-L-arabinofuranoside, quercetin-3-O-${\alpha}$-L -rhamnopyranoside, quercetin-3-O-${\beta}$-D-glucopyranoside, myricetin-3-O-${\beta}$-D-galac-topyranoside, (+)-catechin and (-)-epicatechin.