• Applied Biological Chemistry
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• 제27권3호
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• pp.204-210
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• 1984

일반계 12품종 및 다수계 9품종에 대한 수화속도를 비교하였다. 실온에서의 쌀의 수분흡수 속도 또는 물의 확산 계수는 품종마다 독특한 값을 보였다. 쌀은 수분 흡수 속도에 따라 세 그룹으로 나눌 수 있었다. 일반적으로 식미가 좋은 품종으로 알려진 쌀은 수분 흡수 속도가 낮았으며, 대부분의 다수계 품종은 중간 정도의 수분 흡수 속도를 보였다.

• 생약학회지
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• 제17권2호
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• pp.134-138
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• 1986

Based on a tracer study, starch phosphorylase was implicated as an agent in the starch synthesis in sweet potato roots. The enzyme was purified from the tissue as a cluster of isozymes with an average mw of 205K (fresh roots) or 159K (roots stored for 3 mon.). On SDS polyacrylamide gel electrophoresis, one large subunit of 98K mw and several small ones of 47${\sim}57K mw were observed. From the mw data and the results of peptide mapping and immunoelectrophoretic blotting using mono- and polyclonal antibodies, it was deduced that a large part of the large subunit was cleaved at the middle part of the peptide chain to give rise to the small subunits, and on storage, the enzyme molecules were further modified by proteolysis. During the course of phosphorylase purification, a proteinaceous inhibitor of the enzyme was isolated. It had a mw of 250K and was composed of 5 identical subunits of 51K mw. In the direction of starch synthesis, the inhibitor showed a noncompetitive kinetics with a Ki of $1.3{\times}10^{-6}\;M$. By immunohistochemical methods, both the enzyme and the inhibitor were located on the cell wall and amyloplast. Crossreacting materials of the inhibitor were present in spinach leaf, potato tuber and rice grain. These findings indicate the wide occurrence of the inhibitor and also imply its possible participation in regulating starch phosphorylase activity in vivo.

• Journal of Plant Biotechnology
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• 제45권1호
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• pp.71-76
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• 2018

The Arabidopsis SHL1 (${\underline{Sh}}ort$ ${\underline{L}}ife$ 1) gene encodes a small nuclear protein that is critical for the proper expression of the developmental programs that are responsible for controlling plant stature, senescence, flowering and seed formation. The SHL1 contains a single PHD finger domain that works in conjunction with a bromo-adjacent homology (BAH) motif that is thought to function significantly in protein-protein interactions. The TCH4 gene of the Arabidopsis encodes a xylogluclan endotransglucosylase/hydrolase that is transcriptionally regulated by a variety of hormonal and environmental stimuli. We report here in this study that the SHL1 exhibits sequence specific DNA binding properties, recognizing a 14 bp region of the TCH4 promoter in vitro, spanning nucleotides -262 to -275 (GGAAAAAACTCCCA). Chiefly, the nuclear extracts of Arabidopsis contain a protein with similar binding properties as recombinant SHL1, which is absent in identified transgenic plants that are noted as expressing antisense SHL1 RNA. Interestingly, the SHL1 gene expression with a BL treatment in characteristically wild types of seedlings showed that the transcript level of SHL1 is significantly down regulated by the BL treatment. The SHL1 may play a subtle role in regulating the kinetics of induction of the TCH4 in response to several stimuli in vivo.

• Asian-Australasian Journal of Animal Sciences
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• 제13권8호
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• pp.1084-1093
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• 2000

An in vitro gas production system was used to investigate the influence of various substrate mixtures on a natural mix of rumen microbes by measurement of fermentation end-products. The treatments were combinations of cassava (15.0, 30.0 and 45.0%) with different roughage sources (ruzi grass, rice straw or urea treated rice straw). Microbial biomass, net $^{15}N$ incorporation into cells, volatile fatty acid production, gas volume and rate of gas production increased linearly with increasing levels of cassava inclusion. There was also an effect of roughage source, with rice straw being associated with the lowest values for most parameters whilst similar values were obtained for ruzi grass and urea treated rice straw. The results suggest that microbial growth and fermentation rate increase as a function of readily available carbohydrate in the substrate mixture. A strong linear relationship between $^{15}N$ enrichment, total volatile fatty acid production and gas production kinetics support the suggestion of the use of the in vitro gas production system as a tool for screening feedstuffs as an initial stage of feed evaluation.

• 환경위생공학
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• 제17권3호
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• pp.7-13
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• 2002

The removal efficiency of heavy metals by chitosan complex isolated from biological industrial waste was investigated through laboratory experiments. The results of the study are as follows. The adsorption kinetics of heavy metals were reached the equilibrium adsorption in approximately 30 minutes and the removal efficiency were showed 70.7～97.4%. The effect of temperature on heavy metals adsorption by chitosan complex shows that as the temperature increased, the amount of heavy metals adsorption per unit weight of chitosan complex increased. The correlation between amount of heavy metals adsorption per unit weight of chitosan complex and temperature were obtained through the coefficient of determination($R^2$). $R^2$ values were 0.75(p<0.05), 0.99(p<0.05) and 0.98(p<0.05) in Hg, Mn, and Zn, respectively. The injected chitosan complex in which 0.1 g was adsorpted highly and the removal of heavy metals was found to have the best removal efficiency A linearized Freundlich equation was used to fit the acquired experimental data. As a result, Freundlich constants, the adsorption intensity(I/n) was 0.5564, 0.4074, 0.5244 on the Hg, Mn, Zn, respectively And the measure of adsorption(k) was 2.2144, 1.6963, 2.0792 on the Hg, Mn, Zn, respectively. So, it was concluded that adsorption of heavy metals by chitosan complex is effective.

• Journal of Applied Biological Chemistry
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• 제58권3호
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• pp.209-218
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• 2015

Fructooligosaccharides have been mainly produced by microbial fructosyltransferases (FTase) enzymes. The present work focuses on the optimization of medium composition and cultivation parameters affecting FTase produced by Penicillium aurantiogriseum AUMC 5605 in shake flask cultivation. FTase production was optimized in two steps using DeMeo's fractional factorial design. A 1.46-fold increase in FTase production (105.4 U/mL) was achieved using the optimized culture medium consisting of (g/L): sucrose, 600; yeast extract, 10; $K_2HPO_4$, 5; $MgSO_4{\cdot}7H_2O$, 0.5; $(NH_4)_2SO_4$, 1.0 and KCl, 0.5. The obtained results showed that the maximum FTase enzyme activity was produced at initial cultivation pH values ranging from 6.0-6.5, at agitation speed of 200 rpm and using vegetative fungal cells as inoculum. Moreover, results showed that optimization of medium composition and some cultivation parameters resulted in an increase of about 93.7% in the enzyme activity than the nonoptimized cultivation conditions after 96 h of cultivation. Additionally, maximum production and specific production rates recorded 2340 U/L/h and 102 U/L/h/g cells, respectively.

• Applied Biological Chemistry
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• 제20권1호
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• pp.101-104
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• 1977

Geotrichum candidum이 분비한 lipase를 인산완충용액 중에서 열처리하여 열불활성 곡선을 얻었다. $50^{\circ}C$에서 lipase의 열 불활성 곡선은 고온의 경우와는 달리 일차 반응 속도법칙을 따르지 않았고 고온의 경우에는 일차 반응을 따랐다. $60^{\circ}C$에서의 엔탈피, 엔트로피 및 깁스 자유 에너지의 변화는 각각 120.4 kJ/mol, 73.0 J/mol.K 및 96.9 kJ/mol이었다. 열 불활성 곡선에서 얻은 Geotric hum candidum lipase의 z-value는 $19^{\circ}C$로 pancreas나 우유 중에 존재하는 lipase의 z-value보다 훨씬 큰 값을 나타낸다. 환경인자의 영향으로는 lecithin과 linoleic ac를 첨가하여 열처리 하였는데 실험에 사용한 계면활성제의 농도에서는 별다른 큰 영향을 미치지 않았다.

• Journal of Applied Biological Chemistry
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• 제43권4호
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• pp.230-234
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• 2000

A new method to assay the capsaicinoid synthetase (CS) activity was developed by utilizing NADHcoupled enzyme systems involving pyruvate kinase and lactate dehydrogenase. CS activities in Capsicum placenta, depending upon the kinetics of the NADH oxidation, revealed almost the same profile as compared with those shown using an HPLC-based method. When the substrates, 8-methyl nonanoic acid and vanillylamine, for the CS enzyme were employed separately or simultaneously, it appeared that the two-step reaction, acyl-CoA formation and condensation with vanillyla~ne, of the CS enzyme was a coupled reaction. Thus, this assay method of the CS enzyme can be considered as an alternative to the HPLC-based method, since it has the advantages of rapidity and simplicity as well as reliability when compared with the existing method.

• BMB Reports
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• 제38권3호
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• pp.366-369
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• 2005

NADPH-cytochrome P450 reductase (CPR) transfers electrons from NADPH to cytochrome P450 and also catalyzes the one-electron reduction of many drugs and foreign compounds. Various spectrophotometric assays have been performed to examine electron-accepting properties of CPR and its ability to reduce cytochrome $b_5$, cytochrome c, and ferricyanide. In this report, reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) by CPR has been assessed as a method for monitoring CPR activity. The principle advantage of this substance is that the reduction of MTT can be assayed directly in the reaction medium by a continuous spectrophotometric method. The electrons released from NADPH by CPR were transferred to MTT. MTT reduction activity was then assessed spectrophotometrically by measuring the increase of $A_{610}$. MTT reduction followed classical Michaelis-Menten kinetics ($K_m\;=\;20\;{\mu}M$, $k_{cat}\;=\;1,910\;min^{-1}$). This method offers the advantages of a commercially available substrate and short analysis time by a simple measurement of enzymatic activity of CPR.

• 공업화학
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• 제19권3호
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• pp.277-286
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• 2008

본 논문은 미생물 성장 공정에서의 기질 저해에 관한 modified Haldane 모델의 이론적 유도를 다룬다. 생물학적 개념인 기질-수용체 복합체의 작동 메커니즘을 바탕으로 새로운 미생물학적 동특성인 N-중첩된 다중 기질 저해 모델의 유도와 더불어 일반화가 이론적으로 고찰되었는데, 이것은 효소 반응에서의 단순 기질 저해 메커니즘이 자연스럽게 확장된 것이다. 결과적으로, 본 기질 저해에 관한 modified Haldane 모델은 완전저해 기질농도라는 생물학적 상수를 포함하고 있는, 잘 설계된 4-파라메터 동특성 모델임이 밝혀졌다.