• 생명과학회지
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• 제29권7호
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• pp.755-761
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• 2019

코직산(Kojic acid)은 생리활성물질로서 많이 알려져 있으며 antibacterial, antifungal과 같은 효능을 나타낸다. 또한 티로시나아제(tyrosinase) 억제제로서 작용하여 멜라닌 생성을 저해시키기 때문에 화장품 산업에 있어서도 미백효과를 가지는 중요한 소재로서 각광받고 있다. 본 연구에서는 독립적으로 항산화 효과를 나타내는 유도체와 코직산(Kojic acid)을 연결하여 새로운 기능성을 가지는 신규 화합물을 발굴하고자 하였으며, 클릭 반응(Click reaction)을 통해 트리아졸(triazle)로 연결하여 신규 코직산 컨쥬게이트(conjugated) 화합물을 합성하였다. 먼저 신규 코직산 컨쥬게이트(conjugated) 화합물의 티로시나아제(tyrosinase) 억제 효과에 대해서 연구한 결과 대부분의 화합물이 코직산(Kojic acid)보다 우수한 티로시나아제(tyrosinase) 억제 효과를 나타냈다. 이와 같은 결과로 미루어 보아 신규 코직산 컨쥬게이트(conjugated) 화합물은 항산화용 건강보조식품 조성물 및 항산화 소재, 노화방지 및 미백 기능을 가진 피부외용제 조성물의 유효성분으로 개발될 가능성이 매우 높다고 사료된다.

• Journal of Microbiology and Biotechnology
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• 제4권1호
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• pp.1-6
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• 1994

Continuous culture was carried out with a recombinant Escherichia coli W3110/pCR185, which encodes trp-operon enzymes when the temperature is shifted from $37^{circ}C\;t;42^{\circ}C$. Under derepressed condition of $42^{\circ}C$. plasmlid stability and gene expression were analysed as function of the dilution rate. The stability of plasmid increased with the dilution rate, but maximal levels of gene expression (tryptophan concentration) and plasmid DNA content were obtained at the lowest dilution rate, $0.075\;hr^{-1}$. The plasmid instability, observed at low dilution rates, could be explained by the unbalanced biosynthetic state of the recombinant cell harboring a high copy number of plasmid.

• Journal of Microbiology and Biotechnology
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• 제30권1호
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• pp.1-10
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• 2020

FK506, also known as tacrolimus, is a clinically important immunosuppressant drug and has promising therapeutic potentials owing to its antifungal, neuroprotective, and neuroregenerative activities. To generate various FK506 derivatives, the structure of FK506 has been modified by chemical methods or biosynthetic pathway engineering. Herein, we describe the mode of the antifungal action of FK506 and the structure-activity relationship of FK506 derivatives in the context of immunosuppressive and antifungal activities. In addition, we discuss the neurotrophic mechanism of FK506 known to date, along with the neurotrophic FK506 derivatives with significantly reduced immunosuppressive activity. This review suggests the possibility to generate novel FK506 derivatives as antifungal as well as neuroregenerative/neuroprotective agents.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.799-803
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• 2006

It was reported that an accumulation of Sadenosyl-L-methionine increases production of actinorhodin in Streptomyces lividans and induces antibiotic biosynthetic genes. We also obtained the same result in Streptomyces coelicolor A3(2). Therefore, in order to identify proteins changed by the addition of S-adenosyl-L-methionine in S. coelicolor A3(2), LC/MS/MS analyses were carried out. Thirteen proteins that were not observed in the control were found.

• 약학회지
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• 제34권6호
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• pp.447-456
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• 1990

Various methods are available for the production of L-threonine. The microbial production of L-threonine has been achieved by breeding L-threonine analog-resistant auxotrophic mutants of various bacteria. The enzymatic production of L-threonine has been demonstrated by use of threonine metabolic enzymes such as threonine deaminase, threonine aldolase, or threonine dehydrogenase complex. Threonine synthesis from glycine and ethanol seems to be catalyzed by the enzymes Methanol dehydrogenase(MDH) and Serine hydroxymethyltransferase(SHMT), which was also found to catalyze the aldol condensation of glycine with acetaldehyde. The improved production of L-threonine has been achieved by amplifying the genes for the L-threonine biosynthetic enzymes using recombinant DNA techniques.

• 한국유전체학회:학술대회논문집
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• 한국유전체학회 2002년도 The 11th Korea Genome Conference
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• pp.49.1-49.1
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• 2002

• 자연과학논문집
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• 제17권1호
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• pp.103-111
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• 2006

호알칼리성이며 고온성인 Bacillus sp. TA-11이 세포내로 생성하는 invertase 유전자를 대장균에 클로닝 시켜 얻은 재조합 E. coil pYC17의 invertase 생합성 조절양상을 조사 하였다. 재조합 E. coil의 invertase는 30 mM sucrose에 의해 3시간에 가장 효과적으로 유도 되었으며 조합 E. coil pYC17의 sucrose에 의한 invertase 유도는 10 mM의 glucose 농도에서 심하게 억제 되었다. 이러한 재조합 E. coil pYC17에서의 invertase 생합성 조절 양상은 친주인 Bacillus sp. TA-11과 유사하였으나 저해농도는 낮았다.

• 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.

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1226-1231
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• 2014

The rare actinomycete Pseudonocardia autotrophica was previously shown to produce a solubility-improved toxicity-reduced novel polyene compound named $\underline{N}ystatin$-like $\underline{P}seudonocardia$ $\underline{P}olyene$ (NPP). The low productivity of NPP in P. autotrophica implies that its biosynthetic pathway is tightly regulated. In this study, $wblA_{pau}$ was isolated and identified as a novel negative regulatory gene for NPP production in P. autotrophica, which showed approximately 49% amino acid identity with a global antibiotic down-regulatory gene, wblA, identified from various Streptomycetes species. Although no significant difference in NPP production was observed between P. autotrophica harboring empty vector and the S. coelicolor wblA under its native promoter, approximately 12% less NPP was produced in P. autotrophica expressing the wblA gene under the strong constitutive $ermE^*$ promoter. Furthermore, disruption of the $wblA_{pau}$ gene from P. autotrophica resulted in an approximately 80% increase in NPP productivity. These results strongly suggest that identification and inactivation of the global antibiotic down-regulatory gene wblA ortholog are a critical strategy for improving secondary metabolite overproduction in not only Streptomyces but also non-Streptomyces rare actinomycete species.

• Journal of Microbiology and Biotechnology
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• 제16권6호
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• pp.974-978
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• 2006

The cytochrome P450 monooxygenase from the pikromycin biosynthetic gene cluster in Streptomyces venezuelae, known as PikC, was observed to hydroxylate the unnatural substrate indole to indigo. Furthermore, the site-directed mutagenesis of PikC monooxygenase led to the mutant enzyme F171Q, in which Phe171 was altered to Gln, with enhanced activity for the hydroxylation of indole. From enzyme kinetic studies, F171Q showed an approximately five-fold higher catalytic efficiency compared with the wild-type PikC. Therefore, these results demonstrate the promising application of P450s originating from Streptomyces, normally involved in polyketide biosynthesis, to generate a diverse array of other industrially useful compounds.