• Journal of Microbiology and Biotechnology
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• v.14 no.6
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• pp.1310-1317
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• 2004

The extracellular production of 5-aminolevulinic acid (ALA) by recombinant E. coli BL21 harboring a fusion gene hemA was investigated in a fermenter. For this purpose, the effects of various physiological factors, such as isopropylthio­$\beta$-D-galactopyranoside (IPTG) concentrations and the time of induction, on enzyme activity were studied. Optimum concentrations of glycine and succinic acid were found to be 30 mM and 90 mM, respectively. When the cells were permitted to grow for 2 h prior to the addition of 0.1 mM IPTG, the activity of ALA synthase was higher than when IPTG was initially added. A 36-fold increase in the activity was observed with only 0.1 mM IPTG added. The pH of the medium also influenced the ALA synthase activity with the maximal activity occurring at pH 6.5. In recombinant E. coli extracts, the repeated addition of glycine and D-glucose increased the production of ALA and the inhibited intracellular ALA dehydratase activity, with up to 32 mM ALA being produced in the cultivation.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.6
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• pp.863-868
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• 2004

Lectin activities and chemical characteristics of Escherichia coli, Lactobacillus spp. and Bifidobacterium spp. originating from the porcine cecal mucosal layer were studied based on hemagglutination assay (HA) and hemagglutination inhibition assay (HIA). Although all the bacterial strains were able to agglutinate erythrocytes of porcine or rabbit origin, much higher HA titers were consistently observed for Lactobacillus spp. than for E. coli or for Bifidobacterium spp. A remarkable reduction in HA titers occurred by the treatment of E. coli and Lactobacillus spp. with protease or trypsin and of Bifidobacterium spp. with protease, trypsin or periodate. There were no significant effects on the HA titers of the three groups of bacteria after the treatment with lipase. Hemagglutination of E. coli was strongly inhibited by D (+)-mannose and D (+)-galactose; Lactobacillus spp. by $\alpha$-L-rhamnose and methyl-$\beta$-galactopyranoside; Bifidobacterium spp. by D (+)-alactose, $\alpha$-L-rhamnose, $\alpha$-L-fucose, L (+)-arabinose, D (+)-mannose, D (-)-fructose at a relatively low concentration (1.43 to 3.75 mg/ml). These results, combined with the enhanced HA activities of the three bacterial strains by modification of rabbit erythrocytes with neuraminidase and abolished HA activity of E. coli after treatment with $\beta$-galactosidase, indicate that it might be the glycoproteinous substances surrounding the surface of the bacterial cells that are responsible for the adhesions of these microorganisms by recognizing the specific receptors on the red blood cell.

• Microbiology and Biotechnology Letters
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• v.25 no.3
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• pp.298-304
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• 1997

Thermus caldophilus GK24 was selected as sources of thermostable $\beta$-galactosidase from a survey of genus Thermus. T. caldophilus GK24 (Tca) $\beta$-galactosidase was found to be inducible. The enzyme was optimally active at 75$\circ$C. Enzyme induction was achieved by addition of lactose, galactose and cellobiose to basal media. The addition of glucose to culture media had a repressive effect on further enzyme synthesis. T caldophilus GK24 was tested for production of $\beta$-galactosidase by addition of various concentration of lactose, galactose and cellobiose to standard media. Cellobiose was found to be effective for the $\beta$-galactosidase induction. The optimal induction medium for production of $\beta$-galactosidase was composed of 0.2% cellobiose, 0.3% bactotryptone, 0.3% yeast extract, basal salts and Tris/HCI(pH 7.8). The activity of the enzyme in the optimal induction medium increased nearly 16.5-fold compared to the standard medium. Tca $\beta$-galactosidase was detected when cell extracts was subjected to electrophoresis in a nondenaturing polyacryamide gel and stained for activity with 6-bromo-2-naphtyl-$\beta$-D-galactopyranoside(BNG).

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.516-521
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• 2014

A bacterium producing ${\alpha}$-galactosidase (${\alpha}$-$\small{D}$-galactoside galactohydrolase, EC 3.2.1.22) was isolated. The isolate, KM-1 was identified as Bacillus coagulans based on its 16S rRNA sequence, morphology, and biochemical properties. ${\alpha}$-Galactosidase activity was detected the culture supernatant of B. coagulans KM-1. The bacterium showed the maximum activity for hydrolyzing para-nitrophenyl-${\alpha}$-$\small{D}$-galactopyranoside (pNP-${\alpha}Gal$) at pH 6.0 and $50^{\circ}C$. It hydrolyzed oligomeric substrates such as melibiose, raffinose, and stachyose liberating a galactose residue, indicating that the B. coagulans KM-1 ${\alpha}$-galactosidase hydrolyzed ${\alpha}$-1,6 linkage. The results suggest that the decreased stachyose and raffinose contents in fermented soybean meal are due to the ${\alpha}$-galactosidase activity.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.332-338
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• 2002

A strain YB-4 producing the extracellular $\alpha$-galactosidase was isolated from soil, and has been identified as Streptomyces sp. on the basis of its cultural, morphological and physiological properties. The partially purified $\alpha$-galactosidase was most active on paranitrophenyl-$\alpha$-D-galactopyranoside at pH 6.0 and 6$0^{\circ}C$. The enzyme retained 90% of its maximum activity between pH 4.0 and pH 10.0 after pre-incubation for 1 h. The enzyme was able to hydrolyze oligomeric substrates such as melibiose, raffinose and stachyose to liberate galactose residue, indicating that the $\alpha$-galactosidase of Steptomyces sp. YB-4 hydrolyzed $\alpha$-1,6 linkage.

• Microbiology and Biotechnology Letters
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• v.27 no.4
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• pp.298-303
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• 1999

An $\alpha$-D-galactosidase ($\alpha$-D-galactoside galactohydrolase, EC 3. 2. 1. 22) from earthworm was purified by affinity chromatography using N-$\varepsilon$-aminocaproyl-$\alpha$-D-galactopyranosylamine coupled to sepharose and its properties were examined. The specific activity of the purified enzyme, tested with p-nitrophenyl-$\alpha$-D-galactopyranoside as substrate, was 314 units/mg protein, representing an 122-fold purification of the original crude extract. The final preparation obtained from by Sephadex G-25 chromatography showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight was determined to be 48,000 by SDS-polyacrylamide gel electrophoresis. The purified galactosidase was showed maximum activity at pH 4.5 and 4$0^{\circ}C$, and was stable in the pH and temperature ranges from 4.0 to 5.5 and 30 to 5$0^{\circ}C$, respectively. The enzyme activity was inhibited by Zn2+, Hg2+ and Co2+. When the purified $\alpha$-galactosidase treated to guar gum for 6 hour, gel-promoting property was increased. It was clear that enzymatic elimination of galactose from guar gum by purified $\alpha$-galactosidase would lead to a significant increase in gelation ability.

• Food Science and Biotechnology
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• v.15 no.6
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• pp.908-913
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• 2006

Recombinant ${\beta}$-galactosidase from Bifidobacterium longum LL04 was expressed in Escherichia coli and partially purified by ammonium sulphate precipitation and anion-exchange chromatography (Mono-Q). The optimum temperature and pH of the partially purified enzyme were $50^{\circ}C$ and pH 7.0-8.0, respectively, when o-nitrophenyl-${\beta}$-D-galactopyranoside was used as a substrate. The enzyme was stable over the pH range of 5.0-9.0, and was active at $40^{\circ}C$ for more than 60 min at pH 7.0. The enzyme was significantly activated by $Na^+$ and $K^+$. Maximal activity was observed at the concentration of 10 mM for both $Na^+$ and $K^+$. The enzyme activity was strongly inhibited by most bivalent metal ions. The Km and Vmax on ONPG at 37 and $50^{\circ}C$ were 0.72, 167.9, and 0.507 mM, 310.9 U/mL, respectively.

• Korean Journal of Pharmacognosy
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• v.44 no.1
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• pp.16-21
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• 2013

The fruits of Pourthiaea villosa were extracted with methanol and its extract was fractionated with n-hexane, methylene chloride, ethyl acetate and n-butanol. Repeated column chromatography of silica gel, sephadex LH-20 and HPLC led to the isolation of nine phenolic compounds from ethyl acetate soluble fraction. The chemical structures were elucidated as kaemferol-3-O-${\beta}$-D-glucopyranoside (astragalin) (1), isorhamnetin-3-O-${\beta}$-D-glucopyranoside (2), kaempferol-3-O-${\beta}$-D-xylopyranosyl($1{\rightarrow}2$)-${\alpha}$-L-rhamnopyranoside (3), caffeic acid (4), quercetin-3-O-${\beta}$-D-xylopyranosyl($1{\rightarrow}2$)-a-L-rhamnopyranoside (5), quercetin-3-O-${\beta}$-D-xylopyranosyl($1{\rightarrow}2$)-${\beta}$-D-glucopyranoside (6), quercetin-3-O-${\beta}$-D-xylopyranosyl($1{\rightarrow}2$)-${\beta}$-D-galactopyranoside (7), quercetin-3-O-${\alpha}$-L-rhamnopyranoside (quercitrin) (8), and kaempferol-3-O-${\alpha}$-L-rhamnopyranoside (afzelin) (9) by spectroscopic techniques. These compounds were isolated from this plant for the first time.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.6
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• pp.852-860
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• 2012

An Antarctic bacterial isolate displaying extracellular ${\alpha}$-galactosidic activity was named Paenibacillus sp. LX-20 based on 16S rRNA gene sequence analysis. Optimal activity for the LX-20 ${\alpha}$-galactosidase occurred at pH 6.0-6.5 and $45^{\circ}C$. The enzyme immobilized on the smart polymer Eudragit L-100 retained 70% of its original activity after incubation for 30 min at $50^{\circ}C$, while the free enzyme retained 58% of activity. The enzyme had relatively high specificity for ${\alpha}$-D-galactosides such as p-nitrophenyl-${\alpha}$-galactopyranoside, melibiose, raffinose and stachyose, and was resistant to some proteases such as trypsin, pancreatin and pronase. Enzyme activity was almost completely inhibited by $Ag^+$, $Hg^{2+}$, $Cu^{2+}$, and sodium dodecyl sulfate, but activity was not affected by ${\beta}$-mercaptoethanol or EDTA. LX-20 ${\alpha}$-galactosidase may be potentially useful as an additive for soybean processing in the feed industry.