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

• Toxicological Research
• /
• v.8 no.2
• /
• pp.331-342
• /
• 1992

The chicken major histocompatibility complex (MHC), the B complex, is beginning to be analyzed at the DNA level. Inbred lines of chickens have been reported to possess 3~5 MHC class II genes. To further analyzed the molecular structure of the chicken MHC class II genes, cDNA clones coding for chicken MHC class II (B-L) ${\beta}$ chain molecules were isolated from chicken spleen and liver. Tissue-specific transcription of B-L ${\beta}$genes was studied by Northern blot analysis. A high level of expression was detected for spleen poly(A)$^+$ RNA whereas a faint signal was detected for liver poly(A)$^+$ RNA. Twenty-nine cDNA clones were isolated from the spleen and eight cDNA clones were isolated from the liver. Based on restriction maps, most clones could be clustered into one family of genes. Four cDNA clones were sequenced (S7, S10 and S19 from the spleen and L1, which was identical to S19, from the liver). Complete amino acid sequences of B-L ${\beta}$ chain molecules were predicated from the nucleotide sequences of the cDNA clones. Although both the nature and the location of the conserved residues were similar in chicken and mammalian sequences, some species-specific differences were found, suggesting that the structures of the B-L molecules are similar, but not identical to their mammalian counterparts.

• YAKHAK HOEJI
• /
• v.47 no.6
• /
• pp.450-455
• /
• 2003

Synthesis of (lR,5S,6S)-6-[(lR)-1-hydroxyethyl] -2-[(3S,5S)-5-(2-ethoxycarbonyl-1-moxy(hydroxy)iminoethyl)pyrrolidine-3-ylthio]-1-methylcarbapen-2-em-3-carboxylic acids (10a,l0b) were described. Methyl(2S,4S)-4-tritylthio-1-(allyloxycarbonyl)pyrrolidine-2-carboxyla late (I) was prepared from trans-4-hydroxy-L-proline with (2S,4R)-abs olute configuration as starting material. (2S,4S)-1-allyloxycarbonyl-2-(2-ethoxycarbonyl-hydroxy(methoxy )iminoethyl)-4-mercapto- pyrrolidines (6,7) were obtained from the tritylthio compound (I). (lR,5S,6S)-6-[(lR)-1-hydroxyethyl]-2-[(3S,5S)-5-(2-ethoxycarbonyl-1-methoxy(hydroxy)imino-ethyl)pyrrolidine-3-ylthio]-1-methylcarbapem-2-em-3-carboxylic acids (10a,10b) were obtained by the coupling reaction with carbapenem diphenylphosphates (8) and pyrrolidine-thiol moiety (6,7). Their in vitro antibacterial activities against both Gram-positive and Gram-negative were tested. Compounds ( 10a,10b) showed potent antibacterial activity except pseudomonas aerusinosa.

• Current Research on Agriculture and Life Sciences
• /
• v.7
• /
• pp.153-163
• /
• 1989

The activity changes and biochemical properties of ${\beta}$-gal in tomato fruits during ripening were investigated. The total activity was increased during ripening and three isoenzymes (${\beta}$-gal I, II and III) were purified through DEAE Sephadex A-50 and Sephadex G-100 column chromatography. The activities of ${\beta}$gal isoenzymes (${\beta}$-gal I, II and III) during ripening were 69.8, 31.8 and 170.0 units in mature green phase, while those were 48.7, 88.4 and 136.8 units in Red phase, respectively. As the ripening proceeded the activities of ${\beta}$-gal I and III were some what decreased but the activity of ${\beta}$-gal II was incresed more than 2.8 fold. The optimum pH of ${\beta}$-gal I, II and III were 3.9, 4.2 and 3.9 and the optimum temperature of those were $60^{\circ}C$, $56^{\circ}C$ and $60^{\circ}C$, respectively. All isoenzymes were stable at pH 3.6~6.0 and lost their activity about 50% when it heated at $55^{\circ}C$ for 5 minute. $Mg^{{+}{+}}$-activated the three isoenzymes but $Ca^{{+}{+}}$ and SDS inhibited about 30~40%. $Hg^{{+}{+}}$ inhibited completely. The km value of ${\beta}$-gal I, II and III was 0.36mM, 0.63mM and 0.45mM, reaction rate was rapidly increased until the concentration of substrate was $6.0{\times}10^{-5}M$.

• Microbiology and Biotechnology Letters
• /
• v.37 no.3
• /
• pp.204-212
• /
• 2009

A strain producing ${\alpha}$-galactosidase and ${\beta}$-glucosidase was isolated from Kimchi. The isolated strain was identified as Weissella cibaria by 16S rDNA analysis and designated as Weissella cibaria K-M1-4. The enzyme activity of ${\alpha}$-galactosidase and ${\beta}$-glucosidase reached the maximum in the soy medium at $37^{\circ}C$ for 24 hr. The enzymes were purified by ethanol fractionation, DEAE sepharose fast flow, and sephacryl S-100HR column chromatography. ${\alpha}$-Galactosidase specific activity was shown by 576 Units/mg protein and the yield was 3.5% of the total activity of crude extracts. ${\beta}$-glucosidase specific activity was shown by 480 Units/mg protein and the yield was 2.9% of the total activity of crude extracts. The optimum temperature for ${\alpha}$-galactosidase was $60^{\circ}C$ and 43% of its original activity remained when it was treated at $80^{\circ}C$ for 30 min. For ${\alpha}$-galactosidase shows the optimum pH of 8.0 and is fairly stable between pH5.0 and pH9.0. The enzyme activity was increased in the presence of $Fe^{2+}$ and $Cu^{2+}$. The value of Km and Vmax for the enzyme were 0.98 mM and $1.81{\mu}$mole/min, respectively. The ${\beta}$-glucosidase has the optimum temperature of $50^{\circ}C$ and 46% of its original activity remained when it was treated at $80^{\circ}C$ for 30min. Its optimum pH of 7.0 and is fairly stable between pH5.0 and pH9.0. The enzyme activity was increased in the presence of $Fe^{2+},\;Co^{2+}$ and $Cu^{2+}$. The value of Km and Vmax for the enzyme were 1.24 mM and $6.81{\mu}$mole/min, respectively.

• Journal of the Korean Chemical Society
• /
• v.41 no.9
• /
• pp.465-470
• /
• 1997

A chiral pentadentate ligand, 1,9-bis(S)-prolyl-1,9-dioxo-2,5,8-triaza-nonane, (S,S-prochen) which shows the stereospecific reaction was synthesized from the reaction of S-proline and diethylenetriamine (dien). The red-violet $[Co(SS-prodien)H_2O]ClO_4$ was prepared by the oxidation of the aqueous solution dissolving $CoCl_2{\cdot}6H_2O$ and S,S-prodien. Elemental analysis, electronic absorption spectroscopy, and $^{13}C-NMR$ spectroscopy suggest that the geometrical structure of the Co(III) complex to be an ${\alpha}{\beta}$ (ffm) form, where the dien moiety of the ligand chelates the metal center to comprise a facial isomer, and an aqua ligand coordinates a cis site to the secondary nitrogens of the dien. Based upon the CD spectroscopic analysis, it seems that the absolute configuration of the ${\alpha}{\beta}$(ffm)-$[Co(SS-prodien)H_2O]ClO_4$ has the ${\Lambda}$-form.

• Journal of the Korean Chemical Society
• /
• v.29 no.6
• /
• pp.651-655
• /
• 1985

A series of S-(2,2-diethoxycarbonyl-1-phenylethyl)-L-glutathione derivatives (11a-e) were synthesized from the reaction of ${\beta},\;{\beta}$-diethoxycarbonylstyrene with L-glutathione in 9 : 1 aqueous methanol. Thus, S-(2,2-diethoxycarbonyl-1-phenylethyl)-L-glutathione (11a), S-2,2-diethoxycarbonyl-1-(3',4'-methylenedioxy)phenylethyl-L-glutathione (11b), S-2,2-diethoxycarbonyl-1-(3',4',5'-trimethoxy)phenylethyl-L-glutathione (11c), S-2,2-diethoxycarbonyl-1-(4'-hydroxy)phenylethyl-L-glutathione (11d), S-2,2-diethoxycarbonyl-1-(4'-methoxy)phenylethyl-L-glutathione (11e) were obtained in good yields. The structure of the adducts was characterized by analytical and spectral data. The effects of pH and solvents upon the yields were also briefly examined. In the range of pH from 4.0 to 8.0, the aqueous methanol were found to be the best solvent for the addition reaction and the antibacterial activities of the adducts to Gram(+) bacteria were found to be weak.

• Asian-Australasian Journal of Animal Sciences
• /
• v.6 no.2
• /
• pp.243-248
• /
• 1993

The effect of dietary lipid factors (plant and animal oil, cholesterol and ${\beta}$-sitosterol) on the liver, serum, and egg yolk cholesterol levels of the laying hen was studied. Single Comb White Leghorn laying hens, at 28 weeks of age, were fed two basal diets containing 8.0% soybean oil or 8.0% fish oil, with or without supplemental cholesterol (1.0%), ${\beta}$-sitosterol (2.0%) or combinations of both. Restricting caloric intake resulted in significantly (p<.05) decreased egg production and the total amount of cholesterol excreted via the egg was significantly (p<.05) different among treatment groups. Cholesterol supplementation to the two basal diets resulted in a significant elevation of liver, serum and egg yolk cholesterol levels. The addition of ${\beta}$-sitosterol lowered the cholesterol levels in liver and serum, while increased in the egg yolk (SO + ST, FO + ST). The anticholesterogenic effect of dietary ${\beta}$-sitosterol was not clearly exhibited in this study.

• Microbiology and Biotechnology Letters
• /
• v.13 no.4
• /
• pp.355-359
• /
• 1985

The purified $\beta$-galactosidase from L. sporogenes was most active at pH 7.0 and 6$0^{\circ}C$ with O-nitrophenyl-$\beta$-D-galactopyranoside (ONPG) in 0.05 M phosphate buffer. It was stable over a pH range from 5.0 to 9.0 and lost less than 10％ of its activity after heating for 30 minutes at 6$0^{\circ}C$ and pH 7.0. All the mineral ions examined in this work showed no significant activating effect, whereas L-cysteine exerted a great stimnlatory effect on the enzyme activity at the concentration of 10 mM. The Km values were 1.2 mM for ONPG and 33.3 mM for lactose. Approximately 85％ of lactose in cow's milk, in 10％ skim milk and in 5％ lactose solution was hydrolyzed after 4 hours incubation at 6$0^{\circ}C$ with 2 units of the purified $\beta$-galactosidase per $m\ell$ of the substrate solutions. The $\beta$-galactosidase from L. sporogenes, therefore, is considered to be suitable for hydrolysis of lactose in milk and other dairy products.

• Applied Chemistry for Engineering
• /
• v.16 no.5
• /
• pp.648-652
• /
• 2005

A super ionic conductor, $K^+$-beta-aluminas, which is known to be difficult to obtain in the form of dense sintered density under atmospheric pressure, was pulverized to 350 nm mean particle size using attrition mill. The sample were pressed into tablet form by uniaxial pressing. The specimen was sintered under atmospheric pressure in powder form. Sintering temperature range was $1400^{\circ}C$ to $1650^{\circ}C$ at $50^{\circ}C$ intervals. Additionally, zone sintering was carried out to control the growth grain at high temperature ($1600^{\circ}C$). The density of specimens that were sintered at $1600^{\circ}C$ and $1650^{\circ}C$, and sintered at $1600^{\circ}C$ by zone sintering were about 93% and 95%, respectively. In the case of the lengthened sintering time to 2 h, the density of specimen was reduced to lower than 90%, since the particles were grown to the duplex microstructure.