• Journal of the Korean Chemical Society
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• v.13 no.1
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• pp.96-101
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• 1969

Jalapin purified from the tubers of the sweet potato (Ipomoea batatas) was deacylated and subjected to structural elucidation. Complete and degraded acid hydrolyses indicated the presence of L-rhamnose, D-fucose and D-glucose in the molar ratio of 1: 1: 1 and in the increasing order of acid-stability. While two moles of periodate were consumed per mole of the product, D-glucose survived in the oxidation. The following structure was, therefore, proposed tentatively for the deacylated jalapin: L-$Rha_f$-(1${\to}$4)-D-$Fuc_p$-(1${\to}$3)-D-$Glu_p$-(1${\to}$11)-jalapinolic acid.

• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.265-270
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• 1991

Theoretical calculations on the stabilization energies of framework atoms in hydrolyses Co(Ⅱ )-exchanged zeolite A were made using some potential energy functions and optimization program. The protons which are produced by hydrolysis of $[Co(H_2O)_n]^{2+}$ ion in large cavity showed a tendency to attack the framework oxygen atom O(1) preferentially, and the oxygen atom O(4) within OH- ion was coordinated at Al atom. The weakness of bonds between T(Si, Al) and oxygen by attack of proton and too large coordination number around small aluminum atom will make the framework of Co(Ⅱ)-exchanged zeolite A more unstable. The stabilization energy of $Co_4Na_4$-A framework (- 361.57 kcal/mol) was less than that of thermally stable zeolite A($Na_{12-}$A: - 419.68 kcal/mol) and greater than that of extremely unstable Ba(Ⅱ)-exchanged zeolite A($Ba_{6-}$A: - 324.01 kcal/mol). All the data of powder X-ray diffraction, infrared and Raman spectroscopy of Co(Ⅱ)-exchanged zeolite A showed the evidence of instability of its framework in agreement with the theoretical calculation. Three different groups of water molecules are found in hydrated Co(Ⅱ )-exchanged zeolite A; W(Ⅰ) group of water molecules having only hydrogen-bonds, W(Ⅱ) group water coordinated to $Na^+$ ion, ans W(Ⅲ) group water coordinated to Co(Ⅱ) ion. The averaged interaction energy of each water group shows the decreasing order of W(Ⅲ)>W(Ⅱ)>W(Ⅰ).

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.1
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• pp.27-32
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• 2003

To understand the chemical structure of sewer sludge in comparison with commercial compost and charcoal used as a soil improver, it was carried out to analyse their ash contents and metal ions, and to elucidate the chemical structure of their residuals after a sequential treatment of alcohol-benzene(1:2) extraction in Soxhlet, 3% HCl reflux and 79% H₂SO₄ hydrolysis, using CHNS analyzer and solid C-13 NMR spectrometer. The results obtained were as follows: 1. Ash content of sludge was about 46% that is higher than those of compost (17%) and charcoal (4%). 2. The residual of sludge after a sequential treatment of HCl and H₂SO₄ hydrolyses had high ash content about 23%, too. 3. The sludge seems to be suitable to the soil improver because the content of heavy metal ions in sludge was near the compost and below the organic fertilizer standard. 4. Elemental composition of sludge residual after HCl-H₂SO₄ hydrolyes was C/sub 56/H/sub 91/O/sub 12/N₂S = (C/sub 6/H/sub 10/O/sub 5/)/sub 7/(C/sub 6/H₄)/sub 7/C₂H/sub 43/O₂N₂S, similar to C/sub 103/H/sub 122/O/sub 33/N/sub 6/S = (C/sub 6/H/sub 10/O/sub 5/)/sub 6/(C/sub 6/H₄)/sub 10/C/sub 7/H/sub 22/O₃N/sub 6/S of compost. 5. The sludge residual had proved to have both considerable aliphatic and aromatic groups, but the compost residual to have mainly aliphatic groups and the charcoal to have mainly aromatic groups, through the peak analysis of solid C-13 NMR charts. 6. So, the sewer sludge is proved to have a considerable amount of aromaticity like in woody biomass containing lignin.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.551-566
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• 1997

Phosphorus has been known as an essential component of animal body. However, the requirement has not been determined precisely because of the variable bioavailabilities of feedstuffs from plant origin. The bioavailability of P in various feedstuffs of plant origin varies from 10 to 60%. Digestibility and availability of the P differed considerably depending on the feed. The lowest values were found for maize (under 20%), the highest for wheat and triticale (over 50%). This is due to the proportion of phytate and the presence of intrinsic phytase. And the digestive tract of monogastric animals does not contain sufficient amounts of phytase, an enzyme that hydrolyses the unavailable phytate complexes to available, inorganic orthophosphates. Microbial phytase supplementation improves the P availability, and both intrinsic plant and microbial phytase improves the availability of P in feedstuffs of plant origin. In a mixture of feeds with low and high activity of intrinsic phytase and/or supplemented by commercial phytase, the P availability is additive. However, in the light of current results it seems that exceeding the P availability equal to 60-70% is unrealizable even at large microbial phytase doses.

• The Korean Journal of Food And Nutrition
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• v.10 no.1
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• pp.102-109
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• 1997

The structures of novel branched oligosaccharides synthesized by the acceptor reaction with dextransucrase from Leuconostoc mesenteriodes M-12 were proposed in accordance with the results obtained from enzymatic hydrolyses and a partial acid hydrolysis. The structure of branched oligosaccharide B4 was shown to be 62-O-$\alpha$-D-kojibiosylmaltose. Branched oligosaccharide B5 was shown to be 63-O-$\alpha$-D-kojibiosylpanose. By reacting the acceptor reaction products with endodextranase a novel branched oligosaccharide (D4) could be produced. D4 was derived from the result of endodextranase hydrolysis of oligosaccarides synthesized by the second acceptor reaction with dextransucrase and was resistant to endodextranase and glucoamylase. The proposed structure of D4 was 62-O-$\alpha$-D-kojibiosylisomaltose. Formation pattern of the acceptor reaction products smaller than d.p. 6 with linear or branched linkage was also shown.

• Journal of the Korean Chemical Society
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• v.40 no.4
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• pp.254-263
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• 1996

Five cobalt(Ⅲ) complexes were synthesized from bi- or tridentate nitrogen ligands. Catalytic actions of these complexes for hydrolyses of p-nitrophenyl picolinate, p-nitrophenyl nicotinate, and p-nitrophenyl isonicotinate were investigated by a spectrophotometric method. p-Nitrophenyl picolinate showed the most senstive reaction among three substrates by these catalysts. Aquohydroxo Co(Ⅲ) complexes raised as much as 21∼40 times the rate of hydrolysis of p-nitrophenyl picolinate at pH 6.5. Activities of complexes were in the order: Co(ibpn)(OH)2(OH2) > Co(aepn)(OH)2(OH2) > Co(tn)2(OH)(OH2) > Co (bpy)2(OH)(OH2) > Co(dien)(OH)2(OH2). Catalytic hydrolysis was postulated to proceed through a intramolecular general base catalysis path which is mixed by a partial intramolecular nucleophilic catalysis.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.905-908
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• 2000

Second-order rate constants have been measured spectrophotometrically for the hydrolysis of p-nitrophenyl ac-etate (PNPA) and p-nitrophenyl diphenylphosphinate (PNPDPP) with MO42- (M = Cr, Mo and W) in phos-phate buffer (pH = 8.00) at 35.0 $^{\circ}C.$ Thes e MO42- species exhibit large catalytic effect in the hydrolysis of PNPA and PNPDPP except WO42- in the reaction with PNPA. The catalytic effect of these MO42- species has been observed to be much more significantin the hydrolysis of PNPDPP than in the hydrolysis of PNPA. Since the smallest CrO42-would be most highly solvated by H2O molecules, CrO42- is expected to exhibit the least catalytic effect, if solvation effect is the most important factor. However, in fact, CrO42- shows the highest cat-alytic effect toward PNPA, indicating that solvation effect is not solely responsible for the catalytic effect. The most basic CrO42- shows the highest catalytic effect, while the least basic WO42- is least reactive toward PNPA, indicating that the basicity of MO4 2- might bean important factor. However, in the hydrolysis of PNPDPP, no correlation is observed between the basicity and catalytic effect, suggesting thatbasicity alone can not be re-sponsible for the catalytic effect shown by the MO42- species. Formation of a chelate is suggested to be respon-sible for the high catalytic effect of MO42- in the hydrolysis reaction of PNPA and PNPDPP. The formation of chelate is considered to be more suitable for the reaction with PNPDPP than with PNPA based on the larger catalytic effect observed in the reaction with PNPDPP than with PNPA.

• Journal of Microbiology and Biotechnology
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• v.29 no.1
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• pp.37-43
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• 2019

The gene encoding an ${\alpha}-{\text\tiny{L}}-arabinofuranosidase$ (BvAF) GH51 from Bacillus velezensis FZB42 was cloned and expressed in Escherichia coli. The corresponding open reading frame consists of 1,491 nucleotides which encode 496 amino acids with the molecular mass of 56.9 kDa. BvAF showed the highest activity against sugar beet (branched) arabinan in 50 mM sodium acetate buffer (pH 6.0) at $45^{\circ}C$. However, it could hardly hydrolyze debranched arabinan and arabinoxylans. The time-course hydrolyses of branched arabinan and arabinooligosaccharides (AOS) revealed that BvAF is a unique exo-hydrolase producing exclusively ${\text\tiny{L}}-arabinose$. BvAF could cleave ${\alpha}-(1,2)-$ and/or ${\alpha}-(1,3)-{\text\tiny{L}}-arabinofuranosidic$ linkages of the branched substrates to produce the debranched forms of arabinan and AOS. Although the excessive amount of BvAF could liberate ${\text\tiny{L}}-arabinose$ from linear AOS, it was extremely lower than that on branched AOS. In conclusion, BvAF is the arabinan-specific exo-acting ${\alpha}-{\text\tiny{L}}-arabinofuranosidase$ possessing high debranching activity towards ${\alpha}-(1,2)-$ and/or ${\alpha}-(1,3)-linked$ branches of arabinan, which can facilitate the successive degradation of arabinan by $endo-{\alpha}-(1,5)-{\text\tiny{L}}-arabinanase$.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.304-310
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• 2024

Ricin is a highly toxic protein which is produced in the seeds of the castor oil plant. Ricin toxin A chain has ribosomal RNA N-glycosylase activity that irreversibly hydrolyses the N-glycosidic bond of the adenine residue at position 4324 within the 28S rRNA. In this study, we developed non-toxic recombinant ricin vaccine(R51) in E. coli expression system, and evaluated efficacy of the R51 according to adjuvants. When the R51 was administered using aluminum hydroxide as an adjuvant, the vaccine efficacy was higher than that of TLR agonists or aluminum phosphate. Because it is time-consuming to administer the vaccine three times at three-week intervals, we investigated the survival rate and antibody titer of mice according to the change of time interval of vaccination. Interestingly, there was no difference in survival rate and antibody titer when R51 was administered at 0, 1, and 3 weeks or 0, 2, and 4 weeks compared to when administered at 0, 3, and 6 weeks. Therefore, the developed R51 vaccine is promising to protect soldiers from Ricin attack.

• Korean journal of food and cookery science
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• v.17 no.1
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• pp.65-79
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• 2001

The effects of ${\alpha}$-chymotrypsin and trypsin treatments on the functional properties (degree of hydrolysis, solubility, and emulsifying capacity) of the soy protein isolate prepared from Jinpum soybean milk(JS milk) which has been developed as low lipoxidase-active soybean variety in Korea and extracted from commercially defatted soybean meal milk(DSM milk). The mixing ratios of JS milk to DSM milk were adjusted to 10:0, 7:3, and 5:5, respectively. The general quality attributes(yield, pH, titrable acidity, moisture contents, crude protein contents, color, textural properties, and sensory characteristics) of soybean cheese which has been prepared with the resulting soy protein hydrolysates were evaluated. Jinpum SPI was better subjected to trypsin than ${\alpha}$-chymotrypsin hydrolyses as indicated by better solubility and emulsifying capacity of the hydrolysates. The degree of hydrolysis and solubility of Jinpum SPI were higher than the soybean isolates from DSM milk. The increased ratios of DSM milk in the mixture resulted in the reduced yields and crude protein content along with the lowered titratable acidity while the pH values and moisture contents showed the opposite trends. In color characteristics, the increased amount of DSM milk brought about the significantly lower Hunter color reflectance values of lightness of the cheese products, along with the higher redness and total color difference value(ΔE). However, the enzyme treatment alone was not enough to cause any color differences. The increased ratios of DSM milk also caused the significantly lowered textural parameters such as hardness, adhesiveness and cohesiveness of the soybean cheese. Between the enzyme treatments, the ${\alpha}$-chymotrypsin treated samples resulted in the higher hardness and cohesiveness values of the products than those from the trypsin-treated ones. In organoleptic properties of the product, the better mouthfeel and overall quality scores were obtained from the trypsin treatments as compared with those from the ${\alpha}$-chymotrypsin ones. The mixing ratios of 10:0 and 7:3 were more favored than that of 5:5 as far as mouth-feel, yellowness and overall quality of the products were concerned. On the overall, the mixing ratio of 7:3(JS milk: DSM milk) and the trypsin treatment of the mixture was recommended for better manufacturing of high-quality soybean cheese.