• Animal cells and systems
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• 제10권1호
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• pp.1-6
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• 2006

Previous studies showed that Cdc7 kinase of Schizosaccharomyces pombe phosphorylated the minichromosome maintenance (Mcm) complex efficiently in the presence of spMcm10 protein. The biochemical properties of the phosphorylated Mcm complexes were examined to understand the activation mechanism of the Mcm complex by Cdc7 kinase. The phosphorylation of Mcm complex in the presence of spMcm10 by Cdc7 kinase did not affect the stability of the Mcm complex containing all six subunits, and the changes in the sedimentation properties were not observed after the phosphorylation. The reconstitution of the Mcm complex using the purified proteins showed that the phosphorylation of Mcm2 proteins did not affect the interactions between Mcm proteins. The phosphorylation of the Mcm2-7 complex at the same condition also did not activate the other biochemical activities such as DNA helicase and single stranded (ss) DNA binding activities. On the other hand, spMcm10 protein that was used for the stimulation of Mcm phosphorylation showed single stranded DNA binding activity, and inhibited the DNA helicase activity of the Mcm4/6/7 complex. These inhibitory effects were reduced by the addition of Cdc7 kinase, suggesting that the phosphorylation by Cdc7 kinase decreased the interactions between spMcm10 and the Mcm complex. Taken together, these results suggested that the phosphorylation by Cdc7 kinase alone is not sufficient for the remodeling and the activation of the Mcm complex, and the additional factors or the phosphorylations might be required for the activation of the Mcm complex.

• BMB Reports
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• 제40권5호
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• pp.805-813
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• 2007

Although MCM2 is obviously important for the initiation of eukaryotic DNA replication, its role in $O_2$ dependent regulation of replicon initiation is poorly understood. In this report, I analysed the changes of MCM2 during the transition from hypoxically suppressed replicon initiation to the burst of initiation triggered by reoxygenation in T24 cells. A high level of chromatin bound and nucleosolic MCM2 was found under the hypoxic replicon arrest. In contrast low cytosolic MCM2 was noticed. Recovery of $O_2$ induced phosphorylation and diminution of chromatin bound MCM2, whereas cytosolic MCM2 increased. The level of chromatin bound Cdc7 did not change significantly upon reoxygenation. However, after reoxygenation, significant phosphorylation of Cdc7 and an increase of coimmunoprecipitation with its substrate (MCM2) were observed. This provides a hint that reoxygenation may promote the kinase activity of Cdc7. These changes might be the critical factors in $O_2$ dependent regulation of replicon initiation. Moreover, phosphorylation of Cdc7 by Cdk2 can be observed in vitro, but seems to fail to regulate the level of chromatin bound Cdc7 as well as the changes of MCM2 in response to reoxygenation of hypoxically suppressed cells.

• 한국환경과학회지
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• 제20권7호
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• pp.873-879
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• 2011

Adsorption experiment of carbon dioxide was performed on MCM41 silica impregnated with two kinds of EDA(ethylenediamine) and MEA(monoethanolamine). The prepared adsorbents were characterized by BET surface area, X-ray diffraction and FT-IR. The $CO_2$ capture study was investigated in a U type packed column with GC/TCD. The results of XRD for MCM-41 and amine-impregnated MCM41 showed typical the hexagonal pore system. BET results showed the MCM 41 impregnated amine to have a surface area of 141 $m^2/g$ to 595 $m^2/g$ and FT-IR revealed a N-H functional group at about 1400$cm^{-1}$ to 1600$cm^{-1}$. The $CO_2$ adsorption capacity on EDA and MEA was as follow: MCM41-EDA30 > MCM41 -EDA40 >MCM41-EDA20 >MCM-EDA10 and MCM41-MEA40 >MCM41-MEA30 > MCM41-MEA20> MCM41-MEA10. The MCM41-EDA30 showed the highest adsorption capacity due to physical adsorption and chemical adsorption by amino-group content. The results suggest that mesoporous media with EDA is effective adsorbent for $CO_2$ capture from flue gases.

• Membrane and Water Treatment
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• 제7권6호
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• pp.495-505
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• 2016

Mesoporous MCM-41 was deposited on an inexpensive disk shaped ceramic support through hydrothermal technique for ultrafiltration of $Fe^{3+}$ from aqueous solution. The ceramic support was fabricated using uni-axial compaction technique followed by sintering at $950^{\circ}C$. The characteristics of MCM-41 powder as well as the composite membrane were examined by X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), porosity and pure water permeation test. The XRD result revealed the good crystallinity and well-resolved hexagonally arranged pore geometry of MCM-41. TGA profile of synthesized MCM-41 zeolite displayed the three different stepwise mechanisms for the removal of organic template. The formation of MCM-41 on the porous support was verified by FESEM analysis. The characterization results clearly indicated that the accumulation of MCM-41 by repeated coating on the ceramic disk directs to reduce the porosity and pore size from 47% to 23% and 1.0 to $0.173{\mu}m$, respectively. Moreover, the potential of the fabricated MCM-41 membrane was investigated by ultrafiltration of $Fe^{3+}$ from aqueous stream at various influencing parameters such as applied pressure, initial feed concentration and pH of solution. The maximum rejection 85% was obtained at applied pressure of 276 kPa and the initial feed concentration of 250 ppm at pH 2.

• 생명과학회지
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• 제14권5호
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• pp.732-740
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• 2004

MCM 단백질의 암세포내에서 과발현 되는 원인을 규명하기 위하여 mcm7, 2 promoter영역의 전사인자 결합 부위의 역할을 조사하였다. 암세포에서 promoter 활성은 정상세포보다 8배정도 높은 활성을 나타내 특유 전사인자의 존재를 시사하였다. Promoter영 역 에는 E2F 결합부위 와 Myc/Max/Mad단백질 결합 부위로 알려진 I-box가 존재한다. 이들 각각의 변이체 promoter를 작성하여 암세포와 정상세포에서 luciferase reporter 활성을 측정하는 것으로 각 영역의 역할을 검토하였다. 그 결과 정상세포 내에서는 강한 repressor존재 또는 활성을 negative로 조절 할 수 있는 complex의 존재로 promoter활성이 조절되는 반면 암세포 내에서는 I-box에 결합하여 promoter를 활성화시키는 특유 단백질의 존재가 시사되었다.

• 대한화학회지
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• 제55권4호
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• pp.691-696
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• 2011

CTAB 혹은 CTAB-나피온 촉매를 속빈 실리콘 튜브형 MCM-41에 담지시켰다. 이들 촉매들을 XRD, SEM, BET 등으로 분석하였다. 이들을 1,7-heptanediol 의 브롬화 반응 촉매로 사용하였고 다른 촉매들과 비교하였다. 이들 촉매들은 CTAB 보다 효과가 좋았으며 CTAB-Nafion/MCM-41 이 성능이 가장 우수하였다.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1951-1955
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• 2014

Catalytic pyrolysis of Geodae-Uksae 1, a kind of miscanthus found in Korea, was carried out over mesoporous MCM-48 catalysts. For rapid product analysis and catalyst evaluation, pyrolysis-gas chromatography/mass spectrometry was used. X-ray diffraction, nitrogen sorption, pyridine adsorbed Fourier transform infrared, and NH3 temperature programmed desorption were utilized to analyze the properties of the catalysts. Compared to non-catalytic reaction, catalytic upgrading over mesoporous Al-MCM-48 catalysts produced a higher-quality bio-oil with a high stability and low oxygen content. Al-MCM-48 exhibited higher deoxygenation ability than Si-MCM-48 due to its higher acidity.

• BMB Reports
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• 제41권8호
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• pp.581-586
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• 2008

The pre-replication complex (pre-RC), including the core hexameric MCM2-7 complex, ensures that the eukaryotic genome is replicated only once per cell division cycle. In this study, we identified a rice $\underline{m}ini\underline{c}hromosome$ $\underline{m}aintenance$ (MCM) homologue (OsMCM2) that functionally complemented fission yeast MCM2 (CDC19) mutants. We found OsMCM2 transcript expression in roots, leaves, and seeds, although expression levels differed slightly among the organs. Likewise, the OsMCM2 protein was ubiquitously expressed, but it was downregulated when nutritients were limiting, indicating that MCM2 expression (and therefore cell cycle progression) requires adequate nutrition. Yeast two-hybrid and GST pull-down assays demonstrated that OsMCM2 interacted with the COP9 signalosome 5 (CSN5). Taken as a whole, our results indicated that OsMCM2 functions as a subunit of the rice MCM complex and interacts with CSN5 during developmental regulation.

• 공업화학
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• 제10권7호
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• pp.1096-1098
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• 1999

MCM-41형의 메조포러스 구형 실리카 재료를 염기성 조건에서 양이온 계면활성제를 templating species로 사용하여 합성하였다. 본 실험에서 사용한 계면활성제로는 octyltrimetylammonium bromide, dodecyltrimetylammonium bromide, cetyltrimethylammonium bromide, octadecyltrimethyammonium bromide 및 cetylpyridium bromide이었다. 구형 MCM-41의 비표면적은 $1500m^2/g$나 되었으며 계면활성제의 알킬 사슬의 길이가 길어질수록 기공 크기는 증가하였다.

• 공업화학
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• 제10권7호
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• pp.1020-1027
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• 1999

헤테로폴리산(HPW)을 표면적이 서로 다른 담체인 $SiO_2$ MCM-41, MCM-48에 담지농도와 소성온도를 달리하며 담지시켰다. X-선 회절분석, 질소 흡착법, 적외선 흡수 스펙트럼, $^{31}P$ 고체 핵자기 공명을 통해서 이 담지촉매의 특성을 조사하였다. IR과 NMR의 결과로부터 HPW가 담체안에서 케긴 구조를 유지하면서 존재함을 확인할 수 있었다. MCM-41의 경우에는 35 wt %, MCM-48의 경우에는 65 wt %로 담지시킨 경우에도 X-선 회절패턴에서 HPW 고유의 피크가 나타나지 않았으며, 이와 같은 특성을 통해서 HPW가 고분산 되어 있음을 알 수 있었다. Di, bis, tri-pentaerythritol의 가수분해 반응에서 이들 담지 촉매는 높은 촉매 활성을 보였으며 HPW, $HPW/SiO_2$보다 HPW/MCM-41, 48의 촉매 활성이 더 우수하였다.