• 한국미생물·생명공학회지
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• 제47권4호
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• pp.546-554
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• 2019

This study, for the first time, reports the functional expression of lipase B derived from the yeast Candida antarctica (CALB) in Corynebacterium strain using the Escherichia coli plasmid PK18. The CALB gene fragment encoding a 317-amino-acid protein was successfully obtained from the total RNA of C. antarctica. CALB was readily produced in the Corynebacterium strain without the use of induction methods described in previous studies. This demonstrated the extracellular production of CALB in the Corynebacterium strain. CALB produced in the Corynebacterium MB001 strain transformed with pEC-CALB recombinant plasmid exhibited maximum extracellular enzymatic activity and high substrate affinity. The optimal pH and temperature for the hydrolysis of 4-nitrophenyl laurate by CALB were 9.0 and 40℃, respectively. The enzyme was stable at pH 10.7 in the glycine-KOH buffer and functioned as an alkaline lipase. The CALB activity was inhibited in the presence of high concentration of Mg²⁺, which indicated that CALB is not a metalloenzyme. These properties are key for the industrial application of the enzyme.

• Bulletin of the Korean Chemical Society
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• 제34권9호
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• pp.2741-2746
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• 2013

The immobilization of enzyme is one of the key issues both in the field of enzymatic research and industrialization. In this work, we reported a facile method to immobilize Candida Antarctica lipase B (CALB) in alginate carrier. In the presence of calcium cation, the enzyme-alginate suspension could be cross-linked to form beads with porous structure at room temperature, and the enzyme CALB was dispersed in the beads. Activity of the enzyme-alginate composite was verified by enzymatic hydrolysis reaction of p-nitrophenol butyrate in aqueous phase. The effects of reaction parameters such as temperature, pH, embedding and lyophilized time on the reactive behavior were discussed. Reuse cycle experiments for the hydrolysis of p-nitrophenol butyrate demonstrated that activity of the enzyme-alginate composite was maintained without marked deactivation up to 6 repeated cycles.

• 공업화학
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• 제18권6호
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• pp.643-649
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• 2007

부탄올의 구조이성질체(n-, iso-, sec-, tert-butanol) 와 n-부티르산에 대한 리파아제 효소.촉매 에스테르화 반응이 초임계 이산화탄소 조건 하에서 수행되었다. 본 실험은 교반속도 150 rpm, 반응 온도 323.15 K, 반응 압력 150 bar의 조건으로 고압반응기에서 5 h 동안 수행하였다. 실험에 사용된 리파아제는 Candida Antarctica lipase B (CALB)이다. 실험 결과는 HP-INNOWax 컬럼을 이용하여 FID (Flame Ionization detector)가 장착된 기체 크로마토그래피(Gas Chromatography, GC)를 이용하여 분석하였다. 반응 후 생성물의 전환률과 반응의 경향성을 분자동역학 시뮬레이션을 이용하여 예측된 결과와 정성적으로 비교하였다. 경쟁적인 저해반응이 포함된 Ping-Pong Bi-Bi 메커니즘을 기초로 하여, 반응의 각 단계를 적용하여 구조 최적화를 하였고 이를 이용해 전이상태의 에너지를 구하여 반응의 경향성을 예측하였다. 생성되는 에스테르 이성질체의 구조적 선호도는 분자동역학 시뮬레이션을 통하여 분석하였다. 이러한 방법의 개발은 앞으로 컴퓨터를 이용한 효소 반응의 설계에 유용하게 사용될 수 있을 것이다.

• 한국가금학회지
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• 제44권1호
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• pp.19-28
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• 2017

계란의 난각은 닭의 자궁에서 형성되는 복잡하고 고도화된 다층 석회화 구조이다. 본 연구는 닭의 산란연령에 따른 자궁내막조직의 변화 양상과 난각 형성에 관여하는 주요 유전자들의 발현 양상을 고찰하였다. 난각 형성과 관련하여 난각 단백질과 관련한 OCX-32, OCX-36, OC-17, OC-116 유전자와 난각 이온과 관련한 CALB1, SPP1, SCNN1G, ATP2A2, CA2, CALM1 유전자를 분석대상으로 하였다. 자궁내막조직의 현미경적 관찰 결과, 연령이 증가함에 따라, 자궁 섬모상피세포의 탈락 및 세포의 위축과 섬유화 진행양상이 심화되었다. 그러나 연령 증가에 따른 혈중 이온성분의 농도차이는 없었다. 자궁내막 상피세포의 텔로미어 함량 분석 결과, 산란연령이 증가함에 따라 텔로미어 함유율이 감소됨을 확인하였다. 대부분의 난각 형성 관련 유전자의 발현량은 산란연령에 따라 유의한 변화를 나타내었다. 일부 난각 단백질 관련 유전자의 발현량은 산란연령이 증가함에 따라 증가양상을 보였으나, 이들 유전자들 간의 상호 관련성은 유의한 관계를 보이지 않았다. 난각 형성 이온 관련 유전자인 ATP2A2, SCNN1G, CA2, CALM1 유전자 간에는 상호 밀접한 관련이 있는 것으로 나타났다. 또한 난각 단백질 관련 OCX-32 및 OCX-36 유전자는 대부분의 이온 관련 유전자들과 높은 정의 상관을 보였다. 따라서 OCX-32, OCX-36, CALB-1, ATP2A2, SCNN1G, CA2 및 CALM1유전자들이 난각 형성에 상호 협력하거나 또는 독립적으로 작용한다. 결론적으로 산란연령이 증가함에 따라 자궁내막세포의 손상이 일어나지만, 그럼에도 불구하고 정상적인 난각을 형성할 수 있는 이유는 난각 단백질 및 난각 형성 이온 관련 일부 유전자들이 발현을 조절하여 난각 형성의 항상성 유지하기 때문인 것으로 사료된다.

• 대한소아치과학회지
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• 제43권2호
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• pp.166-175
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• 2016

이전 연구에서 사람의 치수와 치주인대의 기능에 대한 구체적인 3만 2천여개의 인체 유전자의 RNA 활성 정보는 없었다. 본 연구의 목적은 사람 영구치에서 얻은 치주인대와 치수 조직 내의 RNA 유전자 발현을 보고하고 각각의 분자생물학적인 차이를 알아보는 것이다. cDNA 미세배열분석에서 두 조직 사이의 유전자 발현 수준에서 4배 이상 차이나는 유전자는 347개로 밝혀졌으며, 치주인대와 치수에서 각각 83개, 264개의 유전자 발현이 4배 이상 차이난다는 것을 보여주었다. 치주인대는 교원질 합성 (FAP), 교원질 분해 (MMP3, MMP9와 MMP13), 골 형성 및 개조 (SPP1, BMP3, ACP5, CTSK와 PTHLH)와 관련된 유전자가 강하게 발현되었다. 반면 치수조직은 칼슘 이온 (CALB1, SCIN와 CDH12)과 법랑질 또는 상아질의 광화 및 형성 (SPARC/SPOCK3, PHEX, AMBN과 DSPP)와 관련한 유전자의 발현이 높게 나타났다. 이들 유전자 중 SPP1, SPARC/SPOCK3, AMBN, DSPP 등의 유전자는 치아의 기능과 관련해서 잘 알려져 있지만, 다른 유전자들은 microarray 분석을 통해서 새롭게 발견된 유전자이다. 이 유전자들은 추가적인 연구가 수행된다면 재생 치료의 좋은 요인을 찾는데 도움이 될 것으로 생각된다.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1596-1602
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• 2009

A lipase-catalyzed esterification reaction of (S)-naproxen ethyl ester by CALB (Candida antarctica lipase B) enzyme was performed in supercritical carbon dioxide. Experiments were performed in a high-pressure cell for 10 h at a stirring rate of 150 rpm over a temperature range of 313.15 to 333.15 K and a pressure range of 50 to 175 bar. The productivity of (S)-naproxen ethyl ester was compared with the result in ambient condition. The total reaction time and conversion yields of the catalyzed reaction in supercritical carbon dioxide were compared with those at ambient temperature and pressure. The experimental results show that the conversion and reaction rate were significantly improved at critical condition. The maximum conversion yield was 9.9% (216 h) at ambient condition and 68.9% (3 h) in supercritical state. The effects of varying amounts of enzyme and water were also examined and the optimum condition was found (7 g of enzyme and 2% water content).

• Journal of Microbiology and Biotechnology
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• 제17권7호
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• pp.1098-1105
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• 2007

Quantum mechanical and molecular dynamics simulation analysis has been performed on the model system for CALB (Candida antarctica lipase B) with esters to study the reaction mechanism and conformational preference of catalytic hydrolysis and the esterification reaction. Using quantum mechanical analysis, the ping-pong bi-bi mechanism was applied and energies and 3-dimensional binding configurations of the whole reaction pathways were calculated. Further molecular dynamics simulation analysis was performed on the basis of the transition state obtained from quantum mechanical study to observe the effect of structures of the substrates. Calculation results using substrates of different chain length and chiral configurations were compared for conformational preference. The calculated results showed very small influence on chain length, whereas chiral conformation showed big differences. Calculated results from molecular modeling studies have been compared qualitatively with the experimental data using racemic mixtures of (${\pm}$)-cis-4-acetamido-cyclopent-2-ene-1-ethyl acetate as substrates.

• Journal of Microbiology and Biotechnology
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• 제17권8호
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• pp.1308-1315
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• 2007

Lipase B from Candida antarctica (CalB) displayed on the cell surface of H. polymorpha has been functionally improved for catalytic activity by molecular evolution. CalB was displayed on the cell surface by fusing to a cell-wall anchor motif (CwpF). A library of CalB mutants was constructed by in vivo recombination in H. polymorpha. Several mutants with increased whole-cell CalB activity were acquired from screening seven thousand transformants. The two independent mutants CalB 10 and CalB 14 showed an approximately 5 times greater whole-cell activity than the wild-type. When these mutants were made as a soluble form, CalB 10 showed 6 times greater activity and CalB 14 showed an 11 times greater activity compared with the wild-type. Sequence analyses of mutant CALB genes revealed amino acid substitutions of $Leu^{278}Pro$ in CalB10 and $Leu^{278}Pro/Leu^{219}Gln$ in CalB14. The substituted $Pro^{278}$ in both mutants was located near the proline site of the ${\alpha}$10 helix. This mutation was assumed to induce a conformational change in the ${\alpha}$10 helix and increased the $k_{cat}$ value of mutant CalB approximately 6 times. Site-directed mutagenized CalB, LQ ($Leu^{219}Gln$) was secreted into the culture supernatant at an amount of approximately 3 times more without an increase in the CalB transcript level, compared with the wild-type.

• Animal Bioscience
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• 제36권5호
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• pp.740-752
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• 2023

Objective: Dietary phytase increases bioavailability of phytate-bound phosphorus (P) in pig nutrition affecting dietary calcium (Ca) to P ratio, intestinal uptake, and systemic utilization of both minerals, which may contribute to improper bone mineralization. We used phytase to assess long-term effects of two dietary available P (aP) levels using a one-phase feeding system on gene expression related to Ca and P homeostasis along the intestinal tract and in the kidney, short-chain fatty acids in stomach, cecum, and colon, serum, and bone parameters in growing gilts and barrows. Methods: Growing pigs (37.9±6.2 kg) had either free access to a diet without (Con; 75 gilts and 69 barrows) or with phytase (650 phytase units; n = 72/diet) for 56 days. Samples of blood, duodenal, jejunal, ileal, cecal, and colonic mucosa and digesta, kidney, and metacarpal bones were collected from 24 pigs (6 gilts and 6 barrows per diet). Results: Phytase decreased daily feed intake and average daily gain, whereas aP intake increased with phytase versus Con diet (p<0.05). Gilts had higher colonic expression of TRPV5, CDH1, CLDN4, ZO1, and OCLN and renal expression of TRPV5 and SLC34A3 compared to barrows (p<0.05). Phytase increased duodenal expression of TRPV5, TRPV6, CALB1, PMCA1b, CDH1, CLDN4, ZO1, and OCLN compared to Con diet (p<0.05). Furthermore, phytase increased expression of SCL34A2 in cecum and of FGF23 and CLDN4 in colon compared to Con diet (p<0.05). Alongside, phytase decreased gastric propionate, cecal valerate, and colonic caproate versus Con diet (p<0.05). Phytase reduced cortical wall thickness and index of metacarpal bones (p<0.05). Conclusion: Gene expression results suggested an intestinal adaptation to increased dietary aP amount by increasing duodenal trans- and paracellular Ca absorption to balance the systemically available Ca and P levels, whereas no adaption of relevant gene expression in kidney occurred. Greater average daily gain in barrows related to higher feed intake.