• Journal of Korean Society of Forest Science
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• v.35 no.1
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• pp.19-23
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• 1977

Tropical hard wood produces a number of extracts, especially hot-water extracts. The lignin content in the two kinds of bangkirai and red lauan belonging to genus Shorea, was as high as in temperate zone soft wood, mangrove wood of genus Rhizophara contained it on the same level as temperate zone hard wood and keruing of genus Dipterocarpus was in between the two kinds of bangkirau and red lauan, and keruing wood. The xylose content of saccharose composition in the tree of genus Shorea, was as low as in needle-leaved trees, mangrove wood contained it on the same level as broad-leaved trees and the xylose content in keruing wood was in between the above two kinds of wood. The total retrieving rate of alditol acetate acetificated with sulphuric acid and acetic anhydride, did not reach 100%, even if it was supplemented. There was no difficulty in analyzing alditol immediately after acetification but, when it was left for four or five days, the acetificated alditol acetate was dissolved. The pyridine alditol acetificated with pyridine and acetic anhydride, showed the same result.

• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.20-25
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• 1996

Wood chips of oak(Quercus mongolica) and larch(Larix leptolepis) were exploded with the optimum condition. Main components of exploded wood were separated with hot hot water and methanol. The hemicelluloses were purified from hot water extracts and alditol complexs were prepared from purified hemicellulose. And also, cellulose nitrate was prepared from extractive residue and characterized. The results can be summarized as follows. 1. Amounts of carbohydrate(72~79%) in the crude hemicellulose of larch wood was more than those of oak wood(55~66%). 2. The crude hemicelluloses were mainly composed of oligosaccharides in oak wood but those in larch wood contained about 50% monosaccharides. 3. Decolorization of hemicellulose was successful with activated charcoal and ion-exchange resin treatment. The alditol yields were 56.3~82.9%. 4. The degree of substitution(D.S.) of cellulose nitrate was 1.95~2.87 and it showed a good acetone solubility.

• BMB Reports
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• v.40 no.5
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• pp.801-804
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• 2007

The products of reactions catalyzed by Methanococcus. jannaschii (Mj) aldolase using various substrates were identified by gas chromatography (GC). Although Mj aldolase is considered a fuculose-1-phosphate aldolase based on homology searching after gene sequencing, it has not been proven to be a fuculose-1-phosphate aldolase based on its reaction products. Mj aldolase was found to catalyze reactions between glycoaldehyde or D, L-glyceraldehyde and DHAP (dihydroxyacetone phosphate). Before performing GC the ketoses produced were converted into peracetylated alditol derivatives by sequential reactions, i.e., dephosphorylation, $NaBH_4$ reduction, and acetylation. By comparing the GC data of final products with those of standard alditol samples, it was found that the enzymatic reactions with glycoaldehyde, D-glyceraldehyde, and D, L-glyceraldehyde produced D-ribulose-1-phosphate, D-psicose-1-phosphate, and a mixture of D-psicose and L-tagatose-1-phosphate, respectively. These results provide direct evidence that Mj aldolase is a fuculose-1-phosphate aldolase.

• Journal of the Korean Chemical Society
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• v.34 no.6
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• pp.517-526
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• 1990

The crystal structures of two alditol acetates, D-glucitol hexaacetate and xylitol pentaacetate, have been determined by diffraction methods with Mo-K$\alpha$radiation, using direct methods for phase determinations. The crystal data are: for D-glucitol hexaacetate, P2$_1$, with a = 10.275 (2), b = 8.363 (1), c = 12.560 (5) $\AA;\beta$ = 95.97 $(2)^{\circ}$, Z = 2; for xylitol pentaacetate, P2$_1$/C with a = 18.126 (1), b = 11.422 (2), c = 8.649 (1) $\AA$, $\beta = 95.03 (1)^{\circ}$, Z = 4. Both molecules have extended zigzag carbon chain conformations which differ from previous studies of the structures of D-glucitol and xylitol and also differ from NMR studies on alditol acetates. The bond lengths and angles are normal, with mean values over both structures of C($sp^3)-C(sp^3): 1.514 (10),\; C(sp^3)-O: 1.444 (6),\; C(sp^2)-O: 1.347 (9),\; C(sp^2)=O: 1.197 (6),\; C(sp^2)-C(sp^3): 1.479(9){\AA},\; C(sp^3)-C(sp^3)-C(sp^3): 114.6 (17),\; O-C(sp^3)-C(sp^3): 109.4 (23),\; C(sp^2)-O-C(sp^3): 117.4 (6),\; O=C(sp^2)-O: 122.6 (6),\; C(sp^3)-C(sp^2)-O: 111.8 (7),\; C(sp^3)-C(sp^2)=O: 125.5 (4)^{\circ}$. The atoms of acetate groups are in coplanar. There are no particularly short intermolecular contacts and the molecules are held together by van der Waals force only.

• Journal of the Korean Wood Science and Technology
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• v.22 no.2
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• pp.19-24
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• 1994

This study was performed to study utilization of separated carbohydrates as well as separation, following analysis of the major components and separation of the carbohydrates in waste liquors of SP, KP, ASAM and AS. The result can be summerized as follows; Inorganic contents in waste liquors increase in this order AS

• Journal of the Society of Cosmetic Scientists of Korea
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• v.25 no.1
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• pp.6-22
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• 1999

Chitosan oligosaccharide having physiological activity, such as cell proliferation and wound healing, was prepared by NaNO$_2$ oxidation-NaBH$_4$ reduction from natural chitosan. After deamination by NaNO$_2$ oxidation, the reducing-end residue from NaBH$_4$ was converted to alditol unit, and the reduction was checked by MBTH reagent. The resulting chitosan oligosaccharide had a degree of polymeration of 2-6 from HPLC analysis. From moisture absorption test at relative humidity of 43% and 81%, the moisture absorption ability was 63% and 57%. Moisture retention ability at relative humidity of 43%, silica gel emvironment, was 98% and 97% respectively. Cell proliferation was showed In the range of 0.000032~0.01%, wound healing effect was also appeared in the concentration of 2% and 20%. Antioxidative effect ($SC_{50}$/) was 3213 ppm. Chitosan oligosaccharide was compatible with most of ingredients used in cosmetic products.

• Korean Journal of Food Science and Technology
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• v.29 no.6
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• pp.1105-1112
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• 1997

By sequential degradation using partial acid hydrolysis of a weakly acidic polysaccharide (GL-4IIb2'), two acidic oligosaccharide fragments, PA-2' and PA-1-III were isolated and their structures were characterized. PA-2' consisted of almost equal proportion of a rhamnose (Rha) and an unusual sugar, 3-deoxy-D-manno-2-octurosonic acid (Kdo). When permethylated oligosaccharide-alditol derived from PA-2' was analyzed by GC-MS, the peak gave the fragment ions at m/z 189 $(bA_1,\;6-deoxyhexose)$ and at m/z 308 $(aJ_2,\;alditol\;from\;Kdo)$. The peak also gave the characteristic ion at m/z 162 but it did not give the fragment ion at m/z 177, suggesting that Kdo is substituted at C5 but not at C4. Methylation analysis also indicated that PA-2' was composed mainly of terminal Rhap and 5-substituted Kdo. When the reduced product from PA-2' was analyzed by $^1H-NMR$, it gave a signal at 5.09 ppm due to an anomeric proton of ${\alpha}-L-Rha$. These results indicated that PA-2' mainly contained ${\alpha}-L-Rhap-(1{\rightarrow}5)-Kdo$. On the other hand, PA-1-III mainly comprised Rha and Kdo in addition to small proportions of arabinose (Ara) and 3-deoxy-D-lyxo-2-heptulosaric acid (Dha). MS analysis of permethylated oligosaccharide-alditols from PA-1-III suggested that the major peak 1P was $Rhap-(1{\rightarrow}5)-Kdo$ whereas the minor peaks 2P and 3P possessed $Araf-(1{\rightarrow}5)-Dha$ unit and these peaks were produced as epimers during reduction of carbonyl groups in Dha.

• Archives of Pharmacal Research
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• v.17 no.5
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• pp.337-342
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• 1994

Carbohydrate analysis is important in studying structure and activity of complex polysaccharides. New analytical method was applied to get an information on the composition of polysaccharides showing antitumor activity. Monosaccharides were labeled with 7-amino-1, 3-naph-thalenedisulfonic acid (7-AGA) by reductive amination and separated by HPLC. Five kinds of polysaccharides from Basidiomycetes were hydrolyzed and analyzed in combination with electrophresis and HPLC. At the same time, alditol acetate derivatives were prepared and analyzed by gas chromatography. Two different techniques using different derivatization methods showed very similar results. The monosaccharides from Coriolus versicolor and Cordyceps militaris were glucose and galactose. Phellinus linteus composed of glucose, glactose, mannose, arabinose and fucose. The HPLC method with fluorescence detector was very sensitive compared to other methods.

• Bulletin of the Korean Chemical Society
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• v.20 no.10
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• pp.1153-1158
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• 1999

β-Cyclodextrin, amylose, and cellulose were partially methylated and acetylated in order to examine the relative reactivities of 2-, 3-, and 6-OH groups to alkylation and acylation. The partially methylated samples of the polysaccharides were treated with excess of ethyl iodide and sodium hydroxide in dimethyl sulfoxide to convert all of the free hydroxyl groups to ethyl ether groups. The partially O-ethylated and O-methylated polysaccharides were reductively cleaved with triethylsilane in the presence of trimethylsilyl methanesulfonate and borontrifluoride etherate (5 : 1 by mole) and the resulting 4-OH group was acetylated and benzoylated to form mixtures of eight 4-O-acyl-1,5-anhydroalditols. The relative ratio of the alditol esters were analyzed by gas chromatography to determine the degree of substitution at each position. A similar sequence of reactions was carried out with partially acetylated polysaccharides. The results indicated that the order of relative reactivities for methylation are 2-OH > 6-OH > 3-OH and for acylation are 6-OH > 2-OH > 3-OH regardless of the anomeric configuration.

• Applied Biological Chemistry
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• v.36 no.3
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• pp.178-183
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• 1993

Xylose reductase (alditol: $NADP^+$ 1-oxidoreductase, EC 1.1.1.21) from the xylose-fermenting yeast, Candida sp. BT001, was purified via salt fractionation, ion-exchange, gel filtration and affinity chromatography, and its properties were characterized. The enzyme from the yeast was active with both NADPH and NADH as coenzyme. The xylose reductase activity with NADH was approximately 51% of that with NADPH and the specific activities of purified enzyme with NADPH and NADH were 11.78 U/mg and 6.01 U/mg, respectively. Molecular weight of the purified enzyme was 31,000 on SDS-PAGE and 61,000 on gel filtration. The Km for D-xylose, NADPH, and NADH was $94.2{\times}10^{-3}M,\;0.011{\times}10^{-3}M\;and \;0.032{\times}10^{-3}M$, respectively. The purified xylose reductase had relatively higher substrate affinity for L-arabinose than other aldoses tested. The optimal pH was 6.2 and the optimal reaction temperature was $45^{\circ}C$. The thermal stability of the enzyme was for 20 minutes at $30^{\circ}C$.