• 미생물학회지
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• 제48권3호
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• pp.225-227
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• 2012

백색부후균류가 가지는 리그닌 분해효소들은 기질특이성이 넓기 때문에 다양한 난분해성 화합물들을 분해할 수 있다. 본 실험에서는 3가지 다른 방법을 사용하여 laccase와 manganese peroxidase가 각각 도입된 아교버섯 형질전환체의 배양 상등액 효소를 고정화 효소로 만들어 대표적 염료의 하나인 Remazol Brilliant Blue R (RBBR)의 탈색을 실험하였다. 그 결과 알긴산을 효소 용액과 직접 반응하여 만든 고정화 효소에서 48시간 반응 후 약 75% 탈색을 보였다. 비록 한번 사용했던 고정화 효소를 재사용하였을 경우 탈색능이 10-15% 정도 감소되었으나 본 실험에서 제시한 방법이 리그닌 분해효소의 고정화 효소 활용에 기여할 것으로 기대한다.

• Journal of Microbiology and Biotechnology
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• 제24권4호
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• pp.545-555
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• 2014

It has been previously demonstrated that laccases exhibit great potential for use in several industrial and environmental applications. In this paper, two laccase isoenzyme genes, lccB and lccC, were cloned and expressed in Pichia pastoris GS115. The sequence analysis indicated that the lccB and lccC genes consisted of 1,563 and 1,584 bp, and their open reading frames encoded 520 and 527 amino acids, respectively. They had 72.7% degree of identity in nucleotides and 86.7% in amino acids. The expression levels of LccB and LccC were up to 32,479 and 34,231 U/l, respectively. The recombinant laccases were purified by ultrafiltration and $(NH_4)_2SO_4$ precipitation, showing a single band on SDS-PAGE, which had a molecular mass of 58 kDa. The optimal pH and temperature for LccB were 2.0 and $55^{\circ}C$ with 2,2'-azinobis-[ 3-ethylbenzthiazolinesulfonic acid (ABTS) as a substrate, whereas LccC exhibited optimal pH and temperature at 3.0 and $60^{\circ}C$. The apparent kinetic parameters of LccB were 0.43 mM for ABTS with a $V_{max}$ value of 51.28 U/mg, and the Km and $V_{max}$ values for LccC were 0.29 mM and 62.89 U/mg. The recombinant laccases were able to decolorize five types of dyes. Acid Violet 43 (100 g/ml) was completely decolorized by LccB or LccC (2 U/ml), and the decolorization of Reactive Blue KN-R (100 g/ml) was 91.6% by LccC (2 U/ml). Thus, the study characterizes useful laccase isoenzymes from T. versicolor that have the capability of being incorporated into the treatment of similar azo and anthraquinone dyes from dyeing industries.

• Journal of the Korean Wood Science and Technology
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• 제25권2호
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• pp.1-20
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• 1997

목재를 분해시키는 담자균류들은 목재 및 목질복합체에 쉽사리 침투하여 복잡한 리그노셀룰로오스 복합체를 분해시킨다. 이러한 분해에는 많은 효소시스템들이 복합적으로 작용하면서 상호 협동하는 것으로 보고되고 있다. 지금까지 일려진 효소들은 통상 3개의 그룹으로 나눌 수 있는데 그 하나는 목재성분을 직접적으로 공격하는 효소균들, 예를 들면 cellulase complex, laccase(LAC), lignin peroxidase(LIP), horse-radish peroxidase(HRP), manganese-independent peroxidase(MIP) 및 protocatechuate 3,4-dioxygenase(PCD) 등이 있고, 두번째 그룹으로서 manganese-dependent peroxidase(MnP), aryl alcohol oxidase(AAO) 및 glyoxal oxidase(GLO) 등인데, 이들 효소들은 목질을 직접적으로 공격하지 않고 제1그룹의 효소들과 협동하여 작용하는 것으로 알려지고 있다. 제3그룹의 효소들은 glucose oxidase(GOD) 및 cellobiose : quinone oxidoreductase(CBQ)로서 feedback type의 효소들로서 목재고분자의 분해시 대사의 고리를 결합시켜 주는 매우 중요한 기능을 하는 효소군들이다. 그러나 이 이외에도 다른 분해기구가 밝혀지고 있으며 기타 효소들에 의한 리그노셀룰로오스의 분해반응기구의 해명에는 상당한 시간이 걸릴 것으로 사료된다.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2005년도 International Meeting of the Microbiological Society of Korea
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• pp.217.3-217
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• 2005

• 한국동물학회:학술대회논문집
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• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
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• pp.230.3-231
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• 2000

No Abstract, See Full Text

• Journal of the Korean Wood Science and Technology
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• 제26권3호
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• pp.63-72
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• 1998

In order to evaluate the biodegradability and mechanism of 4,5,6-trichloroguaiacol (TCG) produced from bleaching process in pulp mill by Phanerochaete chrysosporium, Trametes versicolor, and Inonotus cuticularis, changes in TCG and its metabolites during biodegradation were analyzed by HPLC, and GC/MS spectrometry. By three fungi, the maximum biodegradability against TCG were very quickly reached, compared with other chlorinated aromatic compounds such as PCP. Within 24 hrs, T versicolor indicated up to 95% of TCG removal rate, and P. chrysosporium and I. cuticularis also showed more than 80%, and 90%, respectively. Particularly, in case of T. versicolor, the removal rate of TCG after 1 hr. incubation was reached to approximately 90%, implying very rapid metabolization of TCG. However, by analyzing the filtrates extracted from TCG containing culture by GC/MS, the major metabolites at initial stage of biodegradation were dimers, indicating that the added TCG monomers were quickly polymerized. The others were trichloroveratrole, dichloroguaiacol, and trichlorobenzoic acid, suggesting that TCG may be biodegraded by several sequential reactions such as polymerization, oxidation, methylation, dechlorination, and hydroxylation. In other experiments, the extracellular fluid which did not contain any fungal mycelia was used to evaluate the effect of mycelia on TCG biodegradation. The extracellular fluid of T. versicolor also biodegraded TCG up to 90% within 24hrs, but those of P. chrysosporium and I. cuticularis did not show any good biodegradability. T versicolor showed the highest value of laccase, and other two fungi indicated a little activity of lignin peroxidase (LiP) and manganese peroxidase (MnP). In addition, the laccase activity of T. versicolor was very linearly proportional to the removal rate of TCG during incubation, in other words, showing the induction effect against TCG. Consequently, the biodegradation of TCG was very dependent upon the activity of laccase.

• 전기화학회지
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• 제7권1호
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• pp.26-31
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• 2004

The direct electrochemical studies of four laccases (plant and fungal laccases) have been investigated on a gold electrode functionalized with a new tether of 2.2'-dithiosalicylic aldehyde. Results from these studies indicate that the redox potential of the active site of plant laccase from Rhus vernificera is shifted to a more negative value(255 mV versus SCE) than that of fungal laccase from Pyricularia oryzae (480 mV versus SCE). Mechanistic studies indicate that the reduction of type-1 Cu precedes the reduction of type-2 and type-3 Cu ions when the electrode is poised initially at different potentials. Also a new tether, 2.2'-dithiosalicylic aldehyde, has been used to study the redox properties of two laccases (LCCI and Lccla) covalently attached to a gold electrode. An irreversible peak at 0.47V vs. SCE is observed in the cyclic voltammorams of LCCI. In contrast, the cyclic voltammograms of LCCIa contain a quasi-reversible peak at 0.18V vs. SCE and an irreversible peak at 0.50V vs. SCE. We find that the replacement of the eleven amino acids a the C-terminus with a single cysteine residue $(i.e., \;LCCI{\rightarrow}LCCIa)$ influences the rate of heterogeneous electron transfer between an electrode and the copper containing active sites $(K_{het}\;for\;LCCI=1.0\times10^{-2}\;s^{-1}\;and\;K_{het}\;for\;LCCI_a= 1.0\;times10^{-1}\;s^{-1}\'at\;0.18V\;versus\;SCE\;and\;4.0\times10^{-2}\;s^{-1}\;at\;0.50V\; versus\;SCE)$. These results show for the first time that the change of the primary structure of a protein via site-directed mutagenesis influences both the redox potentials of the copper ions in the active site and the rate of heterogeneous electron transfer.

• Journal of the Korean Wood Science and Technology
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• 제25권3호
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• pp.29-36
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• 1997

목재부후균으로 부터 락케이스 효소의 생산 및 유도를 위하여 여러가지 유도약품(inducer)을 사용하였다. 이들 가운데 ferulic acid, pentachlorophenol 및 2,5-xylidine이 매우 높은 락케이스 활성을 나타나게 하였으며, 거의 동일한 유도효과를 보여주었다. 이들 약품 이외에도 sinapic acid, syringic acid 및 coffeic acid 등도 높은 락케이스 활성을 주었는데, 산의 형태가 알데히드류보다도 높은 유도효과를 나타냈다. 그리고 실험한 48개 균주 가운데 38개 균주가 락케이스를 생산하였으며, 이 가운데 32균주가 ferulic acid에 의해 강한 효소유도 활성을 보였다. 이러한 결과는 지금까지 락케이스 효소의 검출이 어려웠던 Abortiporus biennis 및 Gleophyllum odoratum에서도 높은 락케이스 효소의 유도를 가능하게 하였다. 아울러 가장 높은 효소활성을 나타낸 균주로서는 Cerrena unicolor 였으며, 그 락케이스 효소활성이 무처리 및 inducer 첨가시 각각 40,000 및 60,000 nkat/l 정도였다.

• Mycobiology
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• 제48권5호
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• pp.373-382
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• 2020

Laccases (EC 1.10.3.2), a group of multi-copper oxidases (MCOs), play multiple biological functions and widely exist in many species. Fungal laccases have been extensively studied for their industrial applications, however, there was no database specially focused on fungal laccases. To provide a comparative genomics platform for fungal laccases, we have developed a comparative genomics platform for laccases and MCOs (http://laccase.riceblast.snu.ac. kr/). Based on protein domain profiles of characterized sequences, 3,571 laccases were predicted from 690 genomes including 253 fungi. The number of putative laccases and their properties exhibited dynamic distribution across the taxonomy. A total of 505 laccases from 68 genomes were selected and subjected to phylogenetic analysis. As a result, four clades comprised of nine subclades were phylogenetically grouped by their putative functions and analyzed at the sequence level. Our work would provide a workbench for putative laccases mainly focused on the fungal kingdom as well as a new perspective in the identification and classification of putative laccases and MCOs.

• 미생물학회지
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• 제55권2호
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• pp.177-179
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• 2019

미국 뉴저지주 중위도 산림토양에서 부식산(천연 복합유기화합물인 부식질의 주요 구성성분) 분해능이 있는 세균 균주 Pseudomonas kribbensis CHA-19를 분리하였으며, 이후 또 다른 토양 유기물인 리그닌과 리그닌 유래의 페룰산(ferulic acid)과 바릴린산(vanillic acid)의 분해능을 확인하였다. 부식질 초기 저분자화 효소(예, dye-decolorizing peroxidase와 laccase-like multicopper oxidase)와 부식질 유래의 다양한 저분자 분해산물들을 분해하는 효소(예, vanillate O-demethylase와 biphenyl 2,3-dioxygenase)를 탐색하기 위해 CHA-19 게놈염기서열을 분석하였다. 최종 확보한 효소유전자 정보는 토양세균의 부식질 분해경로 제안에 사용되었다.