• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.170-175
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• 2022

3-Hydroxypropionic acid (3HP) is a platform chemical and can be converted into other valuable C3-based chemicals. Because a large amount of glycerol is produced as a by-product in the biodiesel industry, glycerol is an attractive carbon source in the biological production of 3HP. Although eight 3HP-producing aldehyde dehydrogenases (ALDHs) have been reported so far, the low conversion rate from 3-hydroxypropionaldehyde (3HPA) to 3HP using these enzymes is still a bottleneck for the production of 3HP. In this study, we elucidated the substrate binding modes of the eight 3HP-producing ALDHs through bioinformatic and structural analysis of these enzymes and selected protein engineering targets for developing enzymes with enhanced enzymatic activity against 3HPA. Among ten AbKGSADH variants we tested, three variants with replacement at the Arg281 site of AbKGSADH showed enhanced enzymatic activities. In particular, the AbKGSADH^R281Y variant exhibited improved catalytic efficiency by 2.5-fold compared with the wild type.

• Journal of Microbiology and Biotechnology
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• 제24권12호
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• pp.1636-1643
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• 2014

3-Hydroxybutyryl-CoA dehydrogenase is an enzyme that catalyzes the second step in the biosynthesis of n-butanol from acetyl-CoA, in which acetoacetyl-CoA is reduced to 3-hydroxybutyryl-CoA. To understand the molecular mechanisms of n-butanol biosynthesis, we determined the crystal structure of 3-hydroxybutyryl-CoA dehydrogenase from Clostridium butyricum (CbHBD). The monomer structure of CbHBD exhibits a two-domain topology, with N- and C-terminal domains, and the dimerization of the enzyme was mostly constituted at the C-terminal domain. The mode of cofactor binding to CbHBD was elucidated by determining the crystal structure of the enzyme in complex with $NAD^+$. We also determined the enzyme's structure in complex with its acetoacetyl-CoA substrate, revealing that the adenosine diphosphate moiety was not highly stabilized compared with the remainder of the acetoacetyl-CoA molecule. Using this structural information, we performed a series of site-directed mutagenesis experiments on the enzyme, such as changing residues located near the substrate-binding site, and finally developed a highly efficient CbHBD K50A/K54A/L232Y triple mutant enzyme that exhibited approximately 5-fold higher enzyme activity than did the wild type. The increased enzyme activity of the mutant was confirmed by enzyme kinetic measurements. The highly efficient mutant enzyme should be useful for increasing the production rate of n-butanol.

• 한국식품저장유통학회지
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• 제11권2호
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• pp.201-206
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• 2004

32종의 생약재를 메탄올로 추출한 후 진공 건조한 후 각추출물의 생리활성 물질 및 알코올 대사와 관련된 효소활성을 측정하였다. DPPH법으로 free radical 소거능을 측정한 결과 정향, 녹차, 목단, 적양은 90% 이상의 소거활성을 보이고, 부위별로 살펴보면 줄기껍질＞ 잎 > 열매 > 뿌리 순으로 활성이 나타났다. 아질산염 소거능은 천초, 적양, 녹차, 지구자목, 팔각향 등이 우수한 소거활성을 보였고, 이 또한 부위별로는 줄기껍질이나 잎에서의 활성이 더 우수한 것으로 나타나 여러 생약재 중 줄기껍질이나 잎에 존재하는 페놀성 화합물이나 flavonoids류가 이와 같은 기능성에 영향을 줄 것으로 간주된다. ADH 활성 측정은 일반적으로 숙취현상에 효과가 있다고 알려져 있는 생약재 13종을 사용하여 알코올 탈수소효소 저해를 측정한 결과 13종의 생약재 모두 90% 이상의 강한 저해효과를 보였다. 그러므로 free radical 소거능이나 아질산염 소거능이 우수한 몇몇 생약재, 즉 녹차, 적양 등은 알코올의 대사와 관련하여 알코올의 대사과정 중 ADH의 활성을 저해하므로써 간 보호 효과와 숙취현상 억제에 효과적이라 사료된다.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1547-1552
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• 2009

Sphingomonas chungbukensis DJ77 has the ability to produce large quantities of an extracellular polysaccharide that can be used as a gelling agent in the food and pharmaceutical industries. We identified, cloned and expressed the UDP-glucose dehydrogenase gene of S. chungbukensis DJ77, and characterized the resulting protein. The purified UDP-glucose dehydrogenase (UGDH), which catalyzes the reversible conversion of UDP-glucose to UDPglucuronic acid, formed a homodimer and the mass of the monomer was estimated to be 46 kDa. Kinetic analysis at the optimal pH of 8.5 indicated that the $K_m\;and\;V_{max}$ for UDP-glucose were 0.18 mM and 1.59 mM/min/mg, respectively. Inhibition assays showed that UDP-glucuronic acid strongly inhibits UGDH. Site-directed mutagenesis was performed on Gly9, Gly12 Thr127, Cys264, and Lys267. Substitutions of Cys264 with Ala and of Lys267 with Asp resulted in complete loss of enzymatic activity, suggesting that Cys264 and Lys267 are essential for the catalytic activity of UGDH.

• Nutrition Research and Practice
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• 제17권6호
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• pp.1113-1127
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• 2023

BACKGROUND/OBJECTIVES: Excessive alcohol consumption has harmful health effects, including alcohol hangovers and alcohol-related liver disease. Therefore, methods to accelerate the alcohol metabolism are needed. Laurus nobilis is a spice, flavoring agent, and traditional herbal medicine against various diseases. This study examined whether the standardized aqueous extract of L. nobilis leaves (LN) accelerates the alcohol metabolism and protects against liver damage in single-ethanol binge Sprague-Dawley (SD) rats. MATERIALS/METHODS: LN was administered orally to SD rats 1 h before ethanol administration (3 g/kg body weight [BW]) at 100 and 300 mg/kg BW. Blood samples were collected 0.5, 1, 2, and 4 h after ethanol administration. The livers were excised 1 h after ethanol administration to determine the hepatic enzyme activity. The alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities in the liver tissue were measured. RESULTS: LN decreased the serum ethanol and acetaldehyde levels in ethanol-administered rats. LN increased the hepatic ADH and ALDH activities but decreased the alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase activities in the ethanol-administered rats. In addition, LN inhibited lipid peroxidation and increased the activities of SOD and GPx. CONCLUSIONS: LN modulates the mediators of various etiological effects of excessive alcohol consumption and enhances the alcohol metabolism and antioxidant activity, making it a potential candidate for hangover treatments.

• 한국식품영양과학회지
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• 제44권12호
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• pp.1785-1792
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• 2015

본 연구에서는 간질환 치료제로 알려진 산겨릅나무 줄기 추출물의 새로운 기능성 소재로서의 개발을 위하여 생리활성을 탐색하였다. 산겨릅나무 열수 추출물의 총 페놀 함량은 198 mg tannic acid equivalents/g으로 나타났다. 항산화활성은 DPPH 및 SOD 활성 측정 방법을 이용하여 분석하였으며, 산겨릅나무 열수 추출물의 농도 0.5 mg/mL에서 각각 89%와 82%의 활성을 나타내었다. 산겨릅나무 추출물의 혈당 강하 효과는 ${\alpha}-glucosidase$ 활성 억제 효과를 측정하였으며, 추출물 $50{\mu}g/mL$ 농도에서 75%의 억제 효과를 나타내었다. 이러한 결과는 지금까지 항당뇨 소재로 사용된 약용작물보다 높은 항당뇨 효과가 있는 것으로 사료된다. 알코올 분해 효소 alcohol dehydrogenase 및 aldehyde dehydrogenase 활성 촉진 효과는 농도 의존적으로 증가하였으며 5 mg/mL 농도에서 각각 260%와 123%를 나타내었다. Lipopolysaccharide에 의하여 유도된 nitric oxide(NO) 합성은 1 mg/mL 농도의 산겨릅나무 추출물을 처리함으로써 NO 합성률이 16.7% 정도 감소하였다. 산겨릅나무 추출물이 tacrine으로 유도된 Hep G2 세포주에 대하여 유의한 보호 활성을 나타냈다. 이러한 결과들은 산겨릅나무 추출물이 우수한 항당뇨, 항염증 효과 및 간세포 보호 효과가 높은 것으로 나타나 기능성 소재로서의 활용 가능성을 확인하였다.

• Korean Chemical Engineering Research
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• 제49권1호
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• pp.101-104
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• 2011

Hemoflavoenzyme으로서 cellobiose dehydrogenase(CDH)는 셀룰로오스를 분해하는 과정에서 세포 외부로 분비되는 효소로서 amorphous cellulose와 강하게 결합하여 셀룰라아제(cellulase)에 의해 microcrystalline cellulose의 가수분해를 증가시킨다. 따라서 CDH는 바이오 에탄올 생산의 당화공정에서 중요한 역할을 할 것으로 예상된다. 여러 백색부후균으로부터 CDH 생산이 높은 Phanerochaete chrysosporium ATCC 32629 균주를 선정하였으며, 균주로부터 생산된 CDH 효소활성의 최적 온도와 pH는 각각 ${55^{\circ}C}$와 4이었다. CDH 활성을 증가시키기 위하여 P. chrysosporium ATCC 32629 균주를 돌연변이시켰다. 돌연변이는 새로운 시도로써 국부적으로 큰 에너지를 줄 수 있는 특징을 가진 양성자 빔을 이용하였다. 양성자 빔 조사 후 사멸율이 약 99.9%인 1.2 kGy에서 CDH 활성이 증가된 변이주를 얻었다. 선별된 변이주와 모균주를 액체배양했을 때 변이주가 모균주보다 CDH와 $\beta$-glucosidase 활성이 각각 약 1.4배와 20배 증가하였다. 따라서, CDH 뿐만 아니라 $\beta$-glucosidase 활성이 높은 P. chrysosporium 변이주를 확보하였다.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 1998년도 제3차 심포지움
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• pp.10-12
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• 1998

• 한국동물학회:학술대회논문집
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• 한국동물학회 1997년도 한국생물과학협회 학술발표대회
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• pp.214.2-214
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• 1997

No Abstract, See Full Text

• 한국동물학회:학술대회논문집
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• 한국동물학회 1997년도 한국생물과학협회 학술발표대회
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• pp.215.1-215
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• 1997

No Abstract, See Full Text