• Korean Journal of Microbiology
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• v.25 no.4
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• pp.304-308
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• 1987

The mode of transglycosylation reaction observed during the action of low-molecular-weight 1,4-$\beta$-D-glucan glucanohydrolase (EC 3.2.1.4) purified from Trichoderma koningii ATCC 26113 was investigated using $^{1}H-NMR $spectroscopy. The H-1 proton resonances were analysed. After reaction of the enzyme with cellotriose, the reaction products were separated by high performance liquid chromatography. H-1 resonances of the products were consisted with those of cellobiose, cellotriose and cellotitraose, respectively. Therefore it was proved that all the reaction products formed by the action of the enzyme on cellooligosaccharides, including transglycosylation products, possess only H-NMR -1,4-glycosidic linkage(s).

• Journal of Applied Biological Chemistry
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• v.55 no.1
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• pp.13-17
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• 2012

In order to enzymatically produce chitooligosaccharide using the crude enzyme preparation from Bacillus cereus D-11, we first studied the optimal reaction conditions. It was found that the optimal temperature for hydrolysis of chitosan was $55^{\circ}C$. The ratio of enzyme/substrate should not be lower than 0.13 U/mg in the reaction mixture. The enzyme activity was stable below $50^{\circ}C$. The products of enzymatic reaction were analyzed by both thin layer chromatography and high performance liquid chromatography. Under the appropriate condition, chitosan was hydrolyzed using the enzyme preparation. The resulting chitooligosaccharides were purified and separated by Dowex ($H^+$) ion exchange chromatography. From 4 g soluble chitosan, 0.95 g $(GlcN)_2$, 1.43 g $(GlcN)_3$, and 1.18 g $(GlcN)_4$ were recovered.

• Journal of the Korean Wood Science and Technology
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• v.38 no.5
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• pp.429-438
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• 2010

In this study, effect of carbon source on the hydrolytic ability of the enzyme from Fomitopsis pinicola, a brown rot fungi, for lignocellulosic biomass were examined on two lignocellulosic biomasses (rice straw and wood) without any pretreatment. Cellulase activities of crude enzyme from F. pinicola, which was cultured on softwood mixture as a carbon source, were 19.10 U/$m{\ell}$ for endo-${\beta}$-1,4-gulcanase (EG), 36.1 U/$m{\ell}$ for ${\beta}$-glucosidase (BGL), 7.27 U/$m{\ell}$ for cellobiohydrolase (CBH), and 7.12 U/$m{\ell}$ for ${\beta}$-1,4 xylosidase (BXL). Softwood mixture as a carbon source in F. pinicola comparatively enhanced cellulase activities than rice straw. The optimal pH and temperature of the cellulase was identified to pH 5 and $50^{\circ}C$for the hydrolysis of rice straw. Under these condition rice straw was hydrolyzed to glucose by the cellulase up to $32.0{\pm}3.1%$ based on the glucan amount of the rice straw for 72 h, while the hydrolytic capability of commercial enzyme (Celluclast 1.5${\ell}$) from rice straw to glucose was estimated to $53.7{\pm}4.7%$ at the same experimental condition. In case of addition of Tween 20 (0.1% w/w, substrate) to the cellulase the hydrolysis of rice straw to glucose was enhanced to $38.1{\pm}2.0%$.

• 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.

• Journal of the Korean Chemical Society
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• v.22 no.3
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• pp.164-172
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• 1978

Carboxypeptidase A-catalyzed hydrolysis of ester substrates was carried out at room temperature in the presence of a number of external reagents. If the acyl-enzyme intermediate, an anhydride, is attacked by the external reagents, products formed by trapping at the acyl portion or at the enzyme portion of the anhydride group can be obtained. Examination of the uv/vis spectral properties of the reaction products and of changes in enzyme activity indicated that such trapping reactions did not occur. Also performed was evaluation of enzymatic rate parameters for the the hydrolysis of O-(o-hydroxyphenylacetyl)-L-${\beta}$-phenyllactate. Detection of 2-coumaranone possibly formed by attack of the o-hydroxy group as an intramolecular trapping group at the acyl-enzyme intermediate was tried, but no evidences for the intramolecular trapping reaction were obtained. Failure to trap the intermediate was discussed in terms of steric hindrance imposed on the approach of the trapping reagents to the anhydride group of the acyl-enzyme intermediate and of the fast enzymatic breakdown of the intermediate.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.439-443
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• 2000

In order to evaluate the safety of greenhouse horticulture products in Korea, we carried out this work by screening of Fusarium species, which produce deoxynivalenol (DON) from greenhouse horticulture in Western Gyeongnam and Northern Gyeongbuk, Korea. For this study, high sensitive enzyme-linked immunosorbent assay, ALP/NADP method, was applied to detection of DON by enzyme amplification system. From 192 samples of greenhouse horticulture soil and its products, 103 isolates of Fusarium species were obtained. The isolates were cultured at 28C for 15 days and the cultured mediums were extracted by ethyl acetate. The production of DON was verified by thin layer chromatography (TLC). As the results of TLC, 8 strains were identified as DON producing strain. We screened potential producers of DON by ALP/NADP. The levels of DON production were shown from 0.007 to 1.21 g/ml of YES medium. The maximum DON producing strain No. 32-D-3 was isolated from soil in Namhae, Korea. In conclusion, the above results indicate that DON producing fungi contaminated greenhouse horticulture products in Korea. Therefore, further studies are required to accumulate more detailed data about the contamination of DON in various cereals.

• Korean Journal of Pharmacognosy
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• v.16 no.1
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• pp.1-6
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• 1985

Effect of various fractions from the roots of Patrinia scabiosaefolia (Valerianaceae) and whole plants of Melandryum firmum (Caryophyllaceae) on enzyme activities in mice was investigated. The butanol fractions from both plants caused a significant elevation of serum transaminase activities when administered intraperitoneally, but did not, orally. Prolonged exposure by oral administration of both plants elevated hepatic cytochrome p-450 content, indicating the induction of drug metabolizing enzymes in liver.

• Journal of Forest and Environmental Science
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• v.24 no.1
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• pp.53-59
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• 2008

Extracellular enzyme activities of Fomitopsis palustris were determined by the particle sizes, culture periods and concentrations of wood particle substrate which was mixture of 4 domestic coniferous woods, such as Pinus densiflora, Larix leptolepsis, Pinus koraiensis, and Pinus rigida. The results showed that the culture conditions had an effect on the secretion of most of the extracellular enzymes from Fomitopsis palustris in the mixed wood particle substrate. :The optimal culture conditions for enzyme activities were 80~100 mesh in wood particle size, 7.5% in concentrations of wood substrate, and 4~8 weeks in culture period.

• Natural Product Sciences
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• v.16 no.1
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• pp.1-5
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• 2010

$\beta$-Glucuronidases (E.C. 3.2.1.31) from Escherichia coli, Helix pomatia, and bovine liver activity have been investigated on 7-O-glucuronides (baicalin, wogonoside, and luteolin-7-O-glucuronide) and 3-O-glucuronides (quercetin-3-O-glucuronide and kaempferol-3-O-glucuronide). Bovine liver enzyme was not active on any of these substrates. E. coli and H. pomatia enzymes were active on 7-O-glucuronides, however, 3-O-glucuronides were resistant to $\beta$-glucuronidase hydrolysis. These results suggest that glucuronic acid at 7-position is more susceptible to E. coli and H. pomatia $\beta$-glucuronidases than that at 3-position. In addition, the subtle difference of aglycone structure on 7-O-glucuronides affected the preference of enzyme. E. coli enzyme was favorable for the hydrolysis of baicalin, however, H. pomatia enzyme was found to be efficient for the hydrolysis of wogonoside. Both enzymes showed the similar hydrolytic activity towards luteolin-7-O-glucuronide. When the Scutellaria baicalensis crude extract was subjected to enzymatic hydrolysis, baicalin and wogonoside were successfully converted to their aglycone counterparts with H. pomatia at 50 mM sodium bicarbonate buffer pH 4.0. Accordingly, the enzymatic transformation of glycosides may be quite useful in preparing aglycones under mild conditions.

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.175.1-175.1
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• 2000