• 한국미생물·생명공학회지
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• 제19권5호
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• pp.464-469
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• 1991

$\alpha$-Amylase를 생산하는 Bacillus sp. 2B를 토양에서 분리하였으며 이 균주에 반복적으로 돌연변이원인 NTG를 처리하여 효소생산성이 증대된 변이주를 유도하였다. $\alpha$-Amylase 고 생산성 균주의 효율적인 획득방법으로 glucose에 의한 $\alpha$-amylase의 생성억제를 받지않는 변이주를 분리한 결과, 효소생산성이 약 30배 향상된 변이주 Bacillus sp. HG4를 획득하였다. 이 균주는 lactose를 탄소원으로 하여 최대 효소생성능을 나타내었으며 빠른 균체성장 및 최대 효소생성시기에 균체 lysis가 적은 점 등 산업적으로 사용하기에 유리한 특성을 가진 것으로 판단된다.

• 미생물학회지
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• 제23권2호
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• pp.77-83
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• 1985

Sophorose에 의한 섬유소분해효소의 유도현상에 있어, Nisizawa등고 Strernbergdh Mandels가 연구보고한 상호 다른 결과들을 재규명하고, sophorose에 의한 섬유소분해효소 합성에 미치는 몇가지 요인들을 조사하고자 본 연구를 행하였다. Sophorose는 Trichoderma reesei QM914에서 CMCase와 ${\beta}-glucosidase$의 합성을 동시에 유도하며, CMCase는 pH 3.0~4.0의 완충용액을 갖는 유도배지에서, ${\beta}-glucosidase$는 pH 5.0~6.0의 K-citrate 완충용액을 갖는 유도배지에서 그 합성이 최대로 유도되었다. 또한, 세포내 ${\beta}-glucosidase$는 pH 6.5의 기질용액에 대하여, 세포의 ${\beta}-glucosidase$는 pH 5.0의 기질용액에 대하여, 각각 최대 활성도를 나타내었다. Methyl ${\beta} D glucosidase$ 는 ${\beta}-glucosidase$의 진정한 유도물질이 아닌 것으로 밝혀졌다. 포도당은 sophorose 에 의한 섬유소분해효소의 유도과정을 억제하며, 이 억제효과는 cAMP의 첨가에 의해서 영향을 받지 아니하였다.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.499-504
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• 1988

Xylan를 기질로 직접 alcohol 발효를 목적으로 각종 토양을 균원시료로 하여 xyla를 분해, 자화하는 효모를 분리하여 동정하고 몇 가지 중요한 성질을 조사하였다. Xylanase를 생산하는 XB-33 효모는 Cryptococcus ater 유연균으로 동정되었다. XB-33 균주의 xylanase 생성은 xylan에 의해 induction되고 xylose나 glucose에 의해서는 repression되었다. 또한 xylan 농도는 1% 수준에서 가장 높았으며, 배양일수 6일째 그 황성이 최고치를 나타내었다. XB-33 균주가 생성 분비하는 xylanase를 DEAE-Sephadex A50으로 colum chromatography 하여 부분 정제한 후 이의 생화학적 특성을 검토한 결과 xylanase의 최적작용 pH는 5.0, 최적 온도는 5$0^{\circ}C$였으며 pH 5.0~7.0에서와 온도 6$0^{\circ}C$ 이하에서 의 효소활성은 비교적 안정하였고 xylan에 대한 xylanase의 작용양상을 조사하기 위해 TLC한 결과 최종산물로서 xylose가 확인되었다. 그리고 xylanase의 xylan에 대한 Km치는 20(mg/ml)이었다.

• Journal of Microbiology and Biotechnology
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• 제17권12호
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• pp.2081-2084
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• 2007

A 2.5 kb aga gene encoding ${\alpha}$-galactosidase (${\alpha}$-Gal) from Leuconostoc mesenteroides SY1 was cloned into pSJE, an E. coli-Leuconostoc shuttle vector. The recombinant plasmid, pSJEaga, was introduced into Leuconostoc citreum KCTC3526 (ATCC49370) by electroporation. Transcription level of aga was the highest in cells grown on raffinose (1%, w/v) followed by cells grown on galactose, melibiose, fructose, glucose, and sucrose. Western blot using antibodies against ${\alpha}$-Gal showed similar results to slot-blot results and enzyme activity measurements. All the results indicated that the aga was successfully expressed in L. citreum and its transcription was under the carbon catabolite repression (CCR).

• BMB Reports
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• 제45권8호
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• pp.458-463
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• 2012

We investigated the mechanisms involved in KHG26377 regulation of glutamate dehydrogenase (GDH) activity, focusing on the roles of SIRT4 and SIRT3. Intraperitoneal injection of mice with KHG26377 reduced GDH activity with concomitant repression of glucose-induced insulin secretion. Consistent with their known functions, SIRT4 ribosylated GDH and reduced its activity, and SIRT3 deacetylated GDH, increasing its activity. However, KHG26377 did not affect SIRT4-mediated ADP-ribosylation/inhibition or SIRT3-mediated deacetylation/activation of GDH. KHG26377 had no effect on SIRT4 protein levels, and did not alter total GDH, acetylated GDH, or SIRT3 protein levels in pancreatic mitochondrial lysates. These results suggest that the mechanism by which KHG26377 inhibits GDH activity and insulin secretion does not involve ADP-ribosylation of GDH by SIRT4 or deacetylation of GDH by SIRT3.

• Journal of Microbiology and Biotechnology
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• 제6권6호
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• pp.425-431
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• 1996

The enzymatic characteristics of Alcaligenes latus were investigated by measuring the variations of various enzyme activities related to biosynthesis and degradation of poly-${\beta}$-hydroxybutyrate (PHB) during cultivation. All PHB biosynthetic enzymes, ${\beta}$-ketothiolase, acetoacetyl-CoA reductase, and PHB synthase, were activated gradually at the PHB accumulation stage, and the PHB synthase showed the highest value among three enzymes. This indicates that the rate of PHB biosynthesis is mainly controlled by either ${\beta}$-ketothiolase or acetoacetyl-CoA reductase rather than PHB synthase. The enzymatic activities related to the degradation of PHB were also measured, and the degradation of PHB was controlled by the activity of PHB depolymerase. The effect of supplements of metabolic regulators, citrate and tyrosine, was also investigated, and the activity of glucose-6-phosphate dehydrogenase was increased by metabolic regulators, especially by tyrosine. The activities of ${\beta}$-ketothiolase and acetoacetyl-CoA reductase were also activated by citrate and tyrosine, while the activity of PHB depolymerase was depressed. The increased rate and yield of PHB biosynthesis by metabolic regulators may be due to the increment of acetyl-CoA concentration either by the repression of the TCA cycle by citrate through product inhibition or by the activation of sucrose metabolism by the supplemented tyrosine.

• 미생물학회지
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• 제30권3호
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• pp.199-206
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• 1992

Six isolated strains degrading aniline were selected, identified and designated as pseudomonas putida K6, Pseudomonas acidovorans K82, Achromobacter gr. D. V. K24, Achromobacter xylosocidans K4, Moraxella sp. K21 and Moraxella sp. K22. All of them degraded 1000 ppm aniline completely within 30 to 36 hours. Most of these strains are resistant to antibiotics more than one, but Moraxella sp. has not any antibiotic marker tested. Most strains except for P. acidovorans K82 were shown to have resistance to the heavy metal ions such as Ni, Cu, Li, Ba, Co, etc. but not to Hg to which only P. putida K6 was resistant. M. sp. K21 was capable of degrading aniline to a maximum concentration of 2500 ppm without any repression. The incubation of the cell in limited pH ranges (4-8) had no great effect on aniline degradation. The addition of bactopeptone to the minimal media promoted the speed of aniline degradation, but the addition of glucose rather repressed the rate of aniline degradation. Through enzyme assay, A. gr. D. V. K 24 was shown to degrade aniline through artho-pathway and formed .betha.-ketoadipate as intermediate metabolite.

• 생명과학회지
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• 제8권4호
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• pp.387-394
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• 1998

A thermophilic bacterium (strain DG0303) producing a thermostable $\alpha$-glucosidase was isolated from manure and identified as Bacillus sp. Strain DG0303 produced high level of $\alpha$-glucosidase compared with other thermophilic Bacillus strains. The cellular protein patterns were also compared with other Bacillus strains by sodium dodecyl sulfatepolyacrylamide gel electrophoresis(SDS-PAGE). On the basis of 16S rDNA analysis the Bacillus sp. DG0303 was found to be a member of Bacillus rDNA group 5. The optimum temperature for growth was 65$\circ$C and no growth was obtained at 40$\circ$C or 75$\circ$C. The optimum pH for growth was 5.5 to 8.5. $\alpha$-glucosidase activity was produced during growth and most activity was detected in the culture supernatant. The $\alpha$-glucosidase production was constitutive in the absence of carbohydrates. High level of enzyme activity was detected when the culture was grown on medium containing starch. Addition of glucose resulted in the repression of the $\alpha$-glucosidase production. The optimum pH and tempoerature for enzyme activity were pH 5.0 and 65$\circ$C, respectively. When analyzed by zymogram, the culture supernatant showed a single $\alpha$-glucosidase band with a molecular weight of approximately 60,000.

• Journal of Microbiology and Biotechnology
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• 제3권1호
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• pp.1-5
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• 1993

The gene for mannose enzyme II of phosphoenolpyruvate-dependent phosphotransferase system from Corynebacterium glutamicum KCTC 1445 was cloned into Escherichia coli ZSC113 using plasmid pBR 322. The recombinant plasmid, designated pCTS3, contained 2.2 kb DNA fragment, and the physical map of the cloned DNA fragment was determined. The E. coli ptsM ptsG mutant transformed with pCTS3 restored glucose and mannose fermentation ability, and grew well on these sugars as the sole carbon source in the minimal medium. The transform ant harboring pCTS3 showed a PTS-mediated repression of growth on maltose by mannose analogue, 2-deoxyglucose. The specificity of the response to 2DG therefore indicates that the cloned DNA fragment carries mannose enzyme II gene.

• 한국미생물·생명공학회지
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• 제5권4호
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• pp.177-184
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• 1977

Arylsulfatase는 간단한 Phenols류의 황에스테르 화합물로부터 S $O_{4}$$^{[-992]}$ - 이온의 유리를 촉매한다. 이 효소는 토양센균을 포함한 많은 미생물과 동식물의 조직등에 널리 분포하여 있으며 이와 같은 넓은 분포는 이 효소의 기본적 기능이 환경학적으로 매우 중요한 의미를 갖는다고 하겠다. Arylsulfatase에 대한보고는 Klebsiella sp를 사용하여 몇몇 보고가 있다. 본 연구는 6종의 Serratia sp를 사용하여 arylsulfatase 합성조건을 검토하고 효소의 정제조건과 성질에 대하여 조사하여 Serratia marcescens를 선정하였다. Serratia mrcescens는 탄소원으로서 xylose rhamnose, glucosamine 그리고 arabinose등과 같은 몇몇 당을 이용하지 못했으며 glucose와 mannitol을 잘 이용하였으나 glucose methioniue의 경우 효소 합성을 억제시키었다. 유황원으로서는 무기유황염과 methionine의 첨가는 억제되었으며 tyramine의 첨가에 의해서 효소 함성의 억제효과는 해제되었다. 효소의 정제는 황산암모늄 포화용액의 분획과 DEAE-Cellulose, CM-Cellulose 그리고 DEAE-Sephadex A-25로 연결되는 구분 분획에 의해서 행하여졌다. 효소의 분자량은 SDS-gelelectrophoresis와 Sephadex G-100 column chromatography에 의하여 각각 46,000과 49,000으로 측정되었고 최적 PH는 6.8이었다. P-Nitrophenyl sulfate를 사용한 Km과 Vmak치는 각각 2.5$\times$$10^{4-}$M과 20 nmoles/min/mg protein이었다. 기질에 대한 특성은 phenylsulfte와 ο-, p-nit-rophenyl sulfate 그리고 p-nitro catechol sulfate에 대해서 높은 활성을 보였다. Hydroxylamine, inorganic fluoride, sulfide 그리고 Phosphate등은 강한 효소 저해작용을 나타내었고 무기유산염은 저해작용을 보여주지 않았다. Tyramine, octopamine그리고 dopamine과 같은 amino acid 또한 강한 저해 작용을 보였다.