• The Korean Journal of Ceramics
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• 제6권4호
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• pp.370-379
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• 2000

Simple ways to build up mixed-metal molecules which can act as potential single-source precursors to multimetallic oxides are reviewed. Emphasis is given to Lewis acid-base reactions between metal alkoxides M(OR)/sub n/, and between metal alkoxides and more accessible oxide precursors, carboxylates M(O₂CR)/sub n/ and β-diketonates M(β-dik)/sub n/. Characterization of the precursors is achieved in the solid state (single crystal X-ray diffraction, FT-IR) and by multinuclear NMR in solution. The reactions proceed toward the formation of aggregates in which the different metals display their usual coordinations numbers, often six for transition metals, as shown. Strategies for fixing the stoichiometry between the metals are developed. The reactivity of the MM species (dissociation, effects of chemical modifiers, of other metallic species, hydrolytic or non-hydrolytic condensation, etc.) will be indicated. Transformations into oxides are illustrated on precursors for titanates or niobates.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2004년도 추계학술대회
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• pp.299-301
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• 2004

A simple procedure for the extraction of the lipolytic enzyme from rice bran has been developed. High activity of lipolytic enzyme was obtained by first defatting the rice bran to remove lipid components with various extraction conditions. Then, after five cycles of aqueous extraction, rice bran lipolytic enzyme was purified using micro- and ultrafiltration apparatus. Lipolytic enzyme activity was estimated by its hydrolytic action of tributyrin. The result indicated that the standard activity curve of butyric acid showed that the potential rice bran enzyme is a hydrolytic lipase enzyme. In addition, it showed higher lipolytic activity and specific enzyme activity with further purification by micro- and ultrafiltration.

• Bulletin of the Korean Chemical Society
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• 제13권4호
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• pp.381-384
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• 1992

The hydrolytic susceptibility of large unilamellar vesicle (LUV) toward cabbage phospholipase D (PLD) was studied. The activity of PLD was determined by pH stat titration method. Using phosphatidylcholine LUV as substrate a pH optimum of 6.96 was observed. For maximal activity the optimal temperature of $31^{\circ}C$ and 10 mM of Ca2+ were required. The apparent Km value estimated was 2.5 mM. The hydrolytic activity of PLD toward PC LUV was somewhat high despite the absence of activator in assay system and this high susceptibility of PC LUV may be attributed to the structural properties of LUV. The effect of amphiphatic substances such as dicetyl phosphate and phosphatidic acid on the enzyme activity were also examined in mixed LUVs.

• 한국동물학회:학술대회논문집
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• 한국동물학회 1998년도 한국생물과학협회 학술발표대회
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• pp.325.1-325
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• 1998

No Abstract, See Full Text

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2004년도 수소연료전지공동심포지움 2004논문집
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• pp.205-210
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• 2004

• 한국식품영양과학회지
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• 제22권3호
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• pp.273-279
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• 1993

박테리아 Bacillus sp. K-295G-7이 생산하는 두유응고효소 I 및 II에 의한 11S globulin (glycinin)의 가수분해 패턴을 조사하였다. 효소 I 과 II에 의한 acidic subunit의 응고시간은 약 4-5 분이었다. 전기 영동의 결과, acidic subunit (A$_3$, M.W=45,000)는 효소반응 2분 이내에 완전히 가수분해되어 분자량 16,000, 20,000의 새로운 band를 형성하였다. 한편 효소 II의 작용으로 약 30,000의 분자량을 가진 분해산물을 생성하였고 효소 I 과 II의 basic subunit 에 대한 가수분해 패턴은 유사하였다.

• Composites Research
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• 제24권4호
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• pp.5-10
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• 2011

환경오염이 나날이 증가함에 따라 바이오 재료에 대한 관심이 커지고 있다. 본 연구에서는 생분해성 열가소성 수지인 폴리 유산 (PLA)을 기지재료로 하고 탄소나노튜브 (CNT)를 나노 filler로 사용하여 압출 및 사출공정을 통하여 복합재료를 제작하였다. 시편의 결정화도를 변화시키기 위하여 어닐링 시간에 변화를 주어 처리하였다. PLA의 결정화 특성은 시차주사열량계 (DSC)를 통하여 평가하였고, 적당한 양의 CNT가 PLA의 결정화 속도를 향상시킨 것을 확인할 수 있었다. 그 외에 PLA/CNT 복합재료의 가수분해 속도는 순수 PLA에 비하여 빠르지만 PLA/CNT 복합재료의 결정화도가 증가함에 따라 가수분해 속도가 늦어지는 것을 확인할 수 있었다. 이것은 가수분해가 PLA/CNT의 계면에서 쉽게 일어나고 결정화도가 높아짐에 따라 분자 구조가 치밀해지기 때문인 것으로 판단 된다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권12호
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• pp.1725-1731
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• 2002

The distribution and activities of hydrolytic enzymes (cellulolyti, hemicellulolytic,pectinolytic and others) in the rumen compartments of Hereford bulls fed 100% alfalfa hay based diets were evaluated. The alfalfa proportion in the diet was gradually increased for two weeks. Whole rumen contents were processed into four fractions: Rumen contents including both the liquid and solid fractions were homogenized and centrifuged, and the supernatant was assayed for enzymes located in whole rumen contents (WRE); rumen contents were centrifuged and the supernatant was assayed for enzymes located in rumen fluids (RFE); feed particles in rumen contents were separated manually, washed with buffer, resuspended in an equal volume of buffer, homogenized and centrifuged and supernatant was assayed for enzymes associated with feed particles (FAE); and rumen microbial cell fraction was separated by centrifugation, suspended in an equal volume of buffer, sonicated and centrifuged, and the supernatant was assayed for enzymes bound with microbial cells (CBE). It was found that polysaccharide-degrading proteins such as $\beta$-1,4-D-endoglucanase, $\beta$-1,4-D-exoglucanase, xylanase and pectinase enzymes were located mainly with the cell bound (CBE) fraction. However, $\beta$-D-glucosidase, $\beta$-D-fucosidase, acetylesterase, and $\alpha$-L-arabinofuranosidase were located in the rumen fluids (RFE) fraction. Protease activity distributions were 37.7, 22.1 and 40.2%, and amylase activity distributions were 51.6, 18.2 and 30.2% for the RFE, FAE and CBE fractions, respectively. These results indicated that protease is located mainly in rumen fluid and with microbial cells, whereas amylase was located mainly in the rumen fluid.

• Journal of the Korean Wood Science and Technology
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• 제38권5호
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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 Microbiology
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• 제41권2호
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• pp.89-94
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• 2003

Bacterial strain No. P08 isolated from wastewater at the Cheongju industrial complex was found to be capable of degrading 4-chlorobenzoate under aerobic condition. P08 was identified as Comamonas sp. from its cellular fatty acid composition and 16S rDNA sequence. The fcb genes, responsible for the hydrolytic dechlorination of 4-chlorobenzoate, were cloned from the plasmid pJJl of Comamonas sp. P08. The fcb gene cluster of comamonas sp. PO8 was organized in the order fcbB-fcbA-fcbTl-fcbT2-fcbT3-fcbC. This organization of the fcb genes was very similar to that of the fcb genes carried on the chromosomal DNA of pseudomonas sp. DJ-12. However, it differed from the fcbA-fcbB -fcbC ordering of Arthrobacter sp. SU. The nucleotide sequences of the fcbABC genes of strain P08 showed 98% and 53% identities to those of Pseudomonas sp. DJ-12 and Arthrobacter sp. SU, respectively. This suggests that the fcb genes might have been derived from Pseudomonas sp. DJ-12 to form plasmid pJSl in Comamonas sp. P08, or that the fcb genes in strain DJ-12 were transposed from Comamonas sp. P08 plasmid.