• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.625-634
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• 2004

The objective of this experiment is to study the possibility of lactate dehydrogenase(LDH) enzyme to prevent lactate accumulation in the rumen, For understanding capacity of bacterial LDH in rumen environments, this study was conducted to explore the effects of temperature, pH, VFAs and metal ions on Lactobacillus sp. FFy111-1's LDH activity, and the LDH activation in rumen fluid accumulated lactate. The optimum pH and temperature of LDH were pH 7.5 and 40$^{\circ}C$, respectively. The LDH activity had a good thennostability at range from 30 to 50$^{\circ}C$. The highest pH stability of the enzyme was at ranges from pH 7.0 to 8.0 and the enzyme activities showed above 64% level of non-treated one at pH 6.0 and 6.5. The LDH was inactivated by VFAs treatments but was enhanced by metal ion treatments without NaCl and $CuSO_4$ Especially, the LDH activity was increased to 127% and 124% of its original activity by 2 mM of $BaCl_2$ and $MnSO_4$, addition, respectively. When the acidic rumen fluid was treated by LDH enzyme of Lactobacillus sp. FFy111-1, the lactate concentration in the rumen fluid was lower compared with non-treated rumen fluid(P<0.05). This lactate reduction was resulted from an action of LDH. It was proved by result of purified D,L-LDH addition that showed the lowest lactate concentration among the treatments(P<0.05). Although further investigation of microbial LDH and ruminal lactate is needed, these findings suggest that the bacterial LDH has the potential capability to decrease the lactate accumulated in an acidic rumen fluid. Also, screening of super LDH producing bacteria and technical development for improving enzyme activity in rumen environment are essential keys for practical application.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.522.1-522
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• 1986

5'-Xanthylic acid 생성균주인 Brevibacterium ammoniagenes ATCC 21263 R에 XMP에서 GMP로의 전환효소인 GMP synthetase활성을 부여하기 위해 동종간 세포융합을 시도하여 융합균주들을 얻었다. 이들 우량 융합균주들과 융합모균의 GMP synthetase 활성을 측정하여 상호 비교하였으며, pH 변화에 따른 GMP synthetase 활성과 GMP 생성량과의 관계를 검토하였다. 또한 최적 pH에서 균성장에 따른 당소모량과 GMP 생성량을 비교하였다.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1977.10a
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• pp.197.5-198
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• 1977

일반적으로 protease는 고정화되면 저분자 기질에 대하여는 높은 활성을 내 주나 고분자 기질에 대하여는 낮은 활성을 나타내 줄다. 이것은 고정화된 Pretense의 구조적인 영향으로 생각된다. 본 실험에서 polysaccharide의 표면에 ac교lamide 및 N-hydroxysuccinmidyl acrylate (NHSA)을 graft 공중합 시킴으로서 긴축쇄에 활성 ester을 가지는 새로운 carrier을 합성하여 Bacillus thermoproteolyticus가 생산하는 중성 pretense인 thermolysin을 고정화시켰으며 아울러 고정화된 thermolysin의 몇가지 효소적 성질을 조사검토 하였다.(중략)

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1976.10a
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• pp.189.4-190
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• 1976

glucose-6-phosphate dehydrogenase를 생산하는 Leuconostoc속 균주를 김치로부터 약 500주 분리하여 그 중 활성이 가장 강한 한주를 분리하여 동정한 결과 Leuconostoc mesenteroides였다. 이 균주로부터 몇가지 효소생산 조건을 실험하여 다음과 같은 결과를 얻었다.(결과)

• The Microorganisms and Industry
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• v.27 no.1
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• pp.2-17
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• 2001

Cyclomaltodextrinase(CDase, EC 3.2.1.54), maltogenic amylase(EC 3.2.1.133). neopullulanase(EC 3.2.1.135)는 cyclomaltodextrin(CD), pullulan 및 전분을 가수분해하는 효소들이다. 이 효소들은 $\alpha$-1,4-Ο-glycosidic 결합에 작용하여 CD와 전분을 말토오스로 pullulan을 panose로 가수분해할 뿐만 아니라 올리고당들을 다양한 당 수용체 분자들의 C-3, C-4. C-6 수산기로 전이시키는 활성도 갖고 있다. 이러한 특성들은 기존의 $\alpha$-amylase를 비롯한 판수화물 분해효소들과 뚜렷이 구별되는 것으로 전분 분해효소들의 분류체계에 새로운 기준점을 제시한다고 하겠다. 본 총설에서는 CDase, maltogenic amylase, neopullulanase처럼 pullulan이나 전분보다 CD를 훨씬 더 잘 분해하는 효소들과 Thermoactinomyces vulgaris amylase II(TVA II)처럼 CD를 분해하기는 하나 pullulan을 더 잘 분해하는 효소들의 생화학적, 효소적, 구조적 특성들을 종합하여 소개하고자 하였다. 이 효소들은 40~60% 정도로 아미노산 서열이 동일하고, 세포 내에 존재하며, 분자량이 62~90 kDa로 $\alpha$-amylase보다 다소 크다. 아미노산 서열 비교분석 및 maltogenic amylase와 TVA II 등의 3차구조 분석 결과, 이 효소들은 아미노 말단에 보통 $\alpha$-amylase에는 존재하지 않는 약 130개 아미노산으로된 영역을 갖고 있어 이를 매개로 이합체를 형성할 수 있는 것으로 나타났다. 이합체-단위체 평형은 염 농도, 효소 농도, 산도 등에 의해 조절되고 단위체와 이합체 모두 효소환성을 갖고 있으나, 기질 특이성이 다르며 단위체는 전분을, 이합체는 CD를 선호하는데 이는 이합체 형성 시 활성부위의 구조적 변화에 따른 것으로 분석되었다. 본 총설에서는 CD 분해효소들의 다양한 기질 특이성을 올리고머 형성 등의 구조적 특성과 관련하여 논함으로써 관련 효소들의 분류체계를 보다 명확히 할 수 있는 자료를 제공하고자 하였으며, 이러한 효소들의 생리적 기능 및 산업적 이용에 대해 제안하고자 하였다.

• Microbiology and Biotechnology Letters
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• v.20 no.5
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• pp.551-558
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• 1992

The extracellular endoinulase from Streptomyces sp. 556 was purified and characterized, The culture broth was fractionated by ammonium sulfate saturation followed by DEAE-cellulose column chromatography and 5ephadex G-200 gel filtration, The ultimately purified fraction revealed a single band in 7.5% polyacrylamide gel electropherogram. The purified enzyme showed the maximal activity at pH 5.5-6.0 and $50^{\circ}C$, but lost 93% of inulase activity after 30 min incubation at $55^{\circ}C$ . The essen.tial amino acid residue for catalytic activity appeared to be tryptophan. This endo inulase was activated by $Mn^{2+}$, whereas inactivated by $Ag^{+}$, $Hg^{+}$, $Cu^{2+}$, $Zn^{2+}$, $Fe^{3+}$ and $Mo^{6+}$ EDTA and 8-hydroxyquinoline inhibited the enzyme so that the enzyme was considered to be a metalloenzyme. The Km value for inulin was 0.287 mM, and no invertase or $\alpha$-glucosidase activity was found in the enzyme.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.13-17
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• 1993

When mandarin orange peel was used for a substrate of citric aCid fermentation by Aspergillus niger, principal enzyme activities were investigated. Not only the activity of polygalacturonase and pectin esterase being capable of digesting pectin and crude fiber of mandarin orange peel. but also that of carboxymethyl cellulase, xylanase and amylase was high. In carbohydrate metabolism, the activity of enzymes related in HMP pathway was higher than that in EMP pathway at the orange peel medium designed hereby rather than synthetic medium. Productivity of citric acid was significantly increased when the activity of citrate synthetase was high and 5imultaneously those of aconitase and NADP-dependent dehydrogenase were low.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.307-310
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• 2004

본 연구에서는 분리대두단백(ISP: isolated soy protein)과 탈지대두박(DSF: defatted soy flake)을 Devolase Flavourzyme 효소로 가수분해한 각각의 HVP를 발효 배지로 사용하여 Candida utilis(KCCM 50342) 효모의 ethylalcohol, 4-ethylguaiacol의 생성과 향 생성의 주요 인자인 a -galactosidase의 활성을 측정하였다. Ethylalcohol은 발효 1일째에 탈지대두박을 원료로 하고 여과후 미생물 처리한 경우에서 가장 높게 생성되었고, 4-ethylguaiacol은 일부 여과하지 않고 미생물 처리한 경우에서 낮은 농도의 생성을 보였다. a-galactosidase 효소활성은 탈지대두박 보다 ISP를 원료로 한 HVP에서 높은 활성을 보였다. 관능검사결과 탈지대두박을 사용한 HVP의 관능적 특성이 ISP를 원료로 한 HVP보다 더 우수하였다. 결과적으로 탈지대두박을 원료로 한 HVP의 향기성분 및 관능적 특성이 우수함을 확인하였다.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.59-65
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• 1993

We isolated Actinomycetes strain GMT 1155 and purified the active compound, MT 1155, on the morphological reversion of ts/NRK cell from the isolate. MT 1155 was identified as toyocamycin having antifungal and antitumor activities from physico-chemical properties and UV, IR, $^1H$-NMR, $^13C$-NMR and mass spectrum. MT 1155 showed the morphologically reversional activity on ts/NRK cell and the cytotoxicity on CTLL cell at the final concentrations of 1.7 JlM and 0.2 11M, respectively and its $IC_{50}$ value on protein kinase A enzyme was 2.3 $\mu$M. Also it had strong antifungal activity against several pathogenic fungi but not antibacterial activity. And it did not inhibit both protein kinase C activity and the bleb-formation of K562 cell induced by phorbol esters.

• Journal of Animal Science and Technology
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• v.50 no.3
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• pp.429-436
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• 2008

A bacterium producing cold-active cellulase and xylanase was isolated from pig feces. The isolate, DK42 strain, was found to be the Gram-positive, non-motile, catalase-positive, and spore-forming stain. Under an electron microscope, the cells were observed to be rod-shaped. The isolate was identified as Bacillus licheniformis DK42 on the basis of morphological and biochemical properties as well as 16S rRNA gene sequences. The characterization of crude cellulase and xylanase from B. licheniformis DK42 was investigated. Cellulase exhibited an optimum temperature and pH at 45℃ and 6.0, whereas xylanase exhibited an optimum temperature and pH at 55℃ and 6.0. Especially cellulase maintained approx. 50% of its maximum activity even at 10℃, indicating that it is cold-active. Both cellulase and xylanase were stable after 2hr at 35℃, whereas they lost their activities after 30min at 65℃.