• Elastomers and Composites
• /
• 제55권3호
• /
• pp.205-214
• /
• 2020

A series of wholly aromatic polyhyroxyamide (PHA) copolymers were prepared by direct polycondensation reaction of isophthalic acid and diacids containing bulky units with 3,3'-dihydroxybenzidine. The inherent viscosities of the PHAs measured at 35℃ in DMAc solution were in the range of 0.31-0.56 dL/g. The solubility study revealed that the PHAs were readily soluble in aprotic solvents such as, dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), and N-methyl-2-pyrrolidone (NMP) at room temperature and in less polar solvent such as pyridine. However, the polybenzoxazole (PBO) copoymers were quite insoluble in all organic solvents except partially soluble in concentrated sulfuric acid and partially soluble in NMP containing LiCl. The PBO copolymers showed maximum weight loss temperature in the range of 593-632℃ and high char yields in the range of 65.0-71.2% at 900℃ in a nitrogen atmosphere.

• 생명과학회지
• /
• 제25권9호
• /
• pp.1021-1026
• /
• 2015

Invertase (β-D-fructosfuranosidase, EC 3.2.1.26)는 설탕을 포도당과 과당으로 가수분해하는 반응을 촉매한다. 3종류의 invertases [액포(수용성 산), 세포질(수용성 알칼리) 및 세포벽 결합]가 식물에서 연구되어 왔다. 우리는 순차적인 ammonium sulfate 침전, 이온교환크로마토그래피, 흡수크로마토그래피, Green-19 친화크로마토그래피 과정을 통해 완두콩(Pisum sativum L.) 발아체로부터 중성 invertase의 세포막 연결 isoform을 430배 순수 분리하였다. 분리된 세포막과 결합 된insoluble invertase (IN-INV)는 최적 pH는 중성에서 알칼리 사이(pH 6.8-7.5)로 나타났다. 이 효소는 Tris 뿐만 아니라 Hg²⁺ and Cu²⁺와 같은 중금속에 의해 저해되었다. IN-INV 의 K_m과 V_max 값은 각각 12.95 mM과 2.98 U/min으로 측정되었다. IN-INV는 기질로써 과당뿐만 아니라 라피노오스와 반응하기 때문에 진정한 β-fructofuranosidase로 판명되었다. IN-INV의 분자량 20 kDa이었다. 위 결과로 볼 때 GA 영향으로 급속히 자라는 발아체에서 단백질이 분리되었는데 특징적으로 invertase였다.

• Journal of Microbiology and Biotechnology
• /
• 제21권8호
• /
• pp.808-817
• /
• 2011

Because of its elevated cellulolytic activity, the filamentous fungus Trichoderma harzianum has a considerable potential in biomass hydrolysis applications. Trichoderma harzianum cellobiohydrolase I (ThCBHI), an exoglucanase, is an important enzyme in the process of cellulose degradation. Here, we report an easy single-step ion-exchange chromatographic method for purification of ThCBHI and its initial biophysical and biochemical characterization. The ThCBHI produced by induction with microcrystalline cellulose under submerged fermentation was purified on DEAE-Sephadex A-50 media and its identity was confirmed by mass spectrometry. The ThCBHI biochemical characterization showed that the protein has a molecular mass of 66 kDa and pI of 5.23. As confirmed by smallangle X-ray scattering (SAXS), both full-length ThCBHI and its catalytic core domain (CCD) obtained by digestion with papain are monomeric in solution. Secondary structure analysis of ThCBHI by circular dichroism revealed ${\alpha}$- helices and ${\beta}$-strands contents in the 28% and 38% range, respectively. The intrinsic fluorescence emission maximum of 337 nm was accounted for as different degrees of exposure of ThCBHI tryptophan residues to water. Moreover, ThCBHI displayed maximum activity at pH 5.0 and temperature of $50^{\circ}C$ with specific activities against Avicel and p-nitrophenyl-${\beta}$-D-cellobioside of 1.25 U/mg and 1.53 U/mg, respectively.

• 한국미생물·생명공학회지
• /
• 제22권6호
• /
• pp.571-576
• /
• 1994

One strain of cellulose-producing Acetobacter was isolated from the traditionally fermen- ted grape vinegar in Korea. The isolated strain, designated as KI strain was identified as the Acetobacter xylinum with respect to physiological and biochemical characteristics. KI produced acetic acid from ethanol, and then decomposed acetate to CO$_{2}$ and H$_{2}$O. When the isolated strain was cultivated statically in broth culture, a thick cellulose pellicle was formed. KI was tolerance of 8% ethanol and 30% glucose, and the isolate was positive in ketogenesis from glycerol, $\gamma$-pyrone from glucose and fructose, and 2-ketogluconic acid from glucose. KI strain possessed straight-chain C$_{18:1}$, C$_{16:0}$, and C$_{14:0}$ fatty acid, and contained ubiquinone Q$_{9}$ and Q$_{10}$ as isoprenoid quinone. DNA base composition of KI strain was 57.6% G+C.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2005년도 생물공학의 동향(XVI)
• /
• pp.478-481
• /
• 2005

In this study optical sensing membrane was developed for the queantification of dissolved carbon dioxide in micro-bioreactor using an immobilized 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt (HPTS). For the immobilization of HPTS sol-gel was synthesied by using 3-glycidoxypropyl-dimethoxymethylsiline and tetraethyl orthosilicate.

• 한국미생물·생명공학회지
• /
• 제44권1호
• /
• pp.106-106
• /
• 2016

• 대한약학회:학술대회논문집
• /
• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
• /
• pp.111-113
• /
• 2003

Biosynthsis of prostaglandin E2 (PGE2), the most common prostanoid with potent and diverse bio-activities, is regulated by three sequential enzymatic steps composed of phospholipase A2, cyclooxygenase (COX), and prostaglandin E synthase (PGES). Recently, three distinct PGESs have been identified; two of them are membrane-bound enzymes, mPGES-1 and mPGES-2, and the third one is a cytosolic enzyme, cPGES. (omitted)

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2005년도 생물공학의 동향(XVII)
• /
• pp.642-643
• /
• 2005

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2005년도 생물공학의 동향(XVII)
• /
• pp.789-790
• /
• 2005

• 한국당과학회:학술대회논문집
• /
• 한국당과학회 2006년도 제1회 연례학술대회
• /
• pp.52-52
• /
• 2006