• Title/Summary/Keyword: pyrophosphate

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Electroplating on Magnesium Alloy in KF-Added Pyrophosphate Copper Bath (불화칼륨이 첨가된 피로인산구리 도금욕에서 마그네슘합금의 전기도금)

  • Lee, Jung Hoon;Kim, Yong Hwan;Jung, Uoo Chang;Chung, Won Sub
    • Korean Journal of Metals and Materials
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    • v.48 no.3
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    • pp.218-224
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    • 2010

  • Direct copper electroplating on Mg alloy AZ31B was carried out in a traditional pyrophosphate copper bath containing potassium fluoride. Electrochemical impedance spectroscopy and polarization methods were used to study the effects of added potassium fluoride on electrochemical behavior. The chemical state of magnesium alloy in the electroplating bath was analyzed by X-ray photoelectron spectroscopy. Adhesion of the copper electroplated layer was also tested. Due to the added potassium fluoride, a magnesium fluoride film was formed in the pyrophosphate copper bath. This fluoride film inhibits dissolution of Mg alloy and enables to electroplate copper directly on it. A dense copper layer was formed on the Mg alloy. Moreover, this copper layer has a good adhesion with Mg alloy substrate.

  • https://doi.org/10.3365/KJMM.2010.48.03.218 인용 KSCI

Cloning of Geranylgeranyl Pyrophosphate Synthase (CrtE) Gene from Kocuria gwangalliensis and Its Functional Co-expression in Escherichia coli (코쿠리아 광안리엔시스의 제라닐제라닐 피로인산염 합성 효소의 클로닝과 대장균에서 공발현을 통한 효소 활성에 관한 연구)

  • Seo, Yong-Bae;Kim, Gun-Do;Lee, Jae-Hyung
    • Journal of Life Science
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    • v.22 no.8
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    • pp.1024-1033
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    • 2012

  • A gene encoding a novel geranylgeranyl pyrophosphate (GGPP) synthase from Kocuria gwangalliensis has been cloned and expressed in Escherichia coli. The deduced amino acid sequence showed 59.6% identity with a putative GGPP synthase (CrtE) from K. rhizophila. An expression plasmid containing the crtE gene was constructed, and E. coli cells containing this plasmid produced a recombinant protein with a theoretical molecular mass of 41 kDa, corresponding to the molecular weight of GGPP synthase. Due to the lack of crtE, crtB, and crtI in E. coli, the biosynthesis of lycopene was only obtained when the plasmid pCcrtE was co-transformed into E. coli expressing the pRScrtBI-carrying carotenoid biosynthesis crtB and crtI genes, which were sub-cloned from Paracoccus haeundaensis. The biochemical studies on the expressed proteins were performed via HPLC. The results obtained from this study will provide a wider base of knowledge regarding the primary structure of CrtE cloned from K. gwangalliensis at the molecular level.

  • https://doi.org/10.5352/JLS.2012.22.8.1024 인용 PDF KSCI

Optimum Condition of Soil Dispersion for Remediating Heavy Metal-Contaminated Soils using Wet Magnetic Separation (중금속 오염 토양 정화를 위한 습식자력선별법 사용 시 최적 토양분산 조건)

  • Chon, Chul-Min;Park, Jeong-Sik;Park, Sook-Hyun;Kim, Jae-Gon;Nam, In-Hyun
    • Economic and Environmental Geology
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    • v.45 no.2
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    • pp.121-135
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    • 2012

  • Soil dispersion and heavy metal leaching with two heavy metal-contaminated soils were studied to derive the optimal dispersion condition in the course of developing the remedial technology using magnetic separation. The dispersion solutions of pyrophosphate, hexametaphosphate, orthophosphate and sodium dodecylsulfate (SDS) at 1 - 200 mM and the pH of solutions was adjusted to be 9 - 12 with NaOH. The clay content of suspension as an indicator of dispersion rate and the heavy metal concentration of the solution were tested at the different pHs and concentrations of the dispersion solution during the experiment. The dispersion rate increased with increasing the pH and dispersion agent concentration of the solution. The dispersion efficiency of the agents showed as follows: pyrophosphate > hexametaphosphate > SDS > orthophosphate. Arsenic leaching was sharply increased at 50 mM of phosphates and 100 mM of SDS. The adsorption of $OH^-$, phosphates and dodecysulfate on the surface of Fe- and Mn-oxides and soil organic matter and the broken edge of clay mineral might decrease the surface charge and might increase the repulsion force among soil particles. The competition between arsenic and $OH^-$, phosphates and dodecylsulfate for the adsorption site of soil particles might induce the arsenic leaching. The dispersion and heavy metal leaching data indicate that pH 11 and 10 mM pyrophosphate is the optimum dispersion solution for maximizing dispersion and minimizing heavy metal leaching.

  • https://doi.org/10.9719/EEG.2012.45.2.121 인용 PDF KSCI

Celluomonas sp. AP-7이 생산하는 Ascorbic Acid Phosphorylating Enzyme의 정제 및 특성

  • 이상협;최현일;방원기
    • Microbiology and Biotechnology Letters
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    • v.25 no.3
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    • pp.271-276
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    • 1997

  • An ascorbic acid phosphorylating enzyme, which catalyzes the formation of ascorbic acid-2-phosphate from ascorbic acid and pyrophosphate, was purified 32.7-folds to homogeneity from a cell-free extract of Cellulomonas sp. AP-7. The combination of DEAE- Sephacel ion exchange chromatography and Sephacryl S-200 get filtration was used for their purification. The molecular weight of the native protein was estimated to be 96.lkDa on high performance gel filtration chromatography. The SDS-PAGE analysis indicated that the protein consisted of four identical subunits of 24.6 kDa. The purified enzyme showed the optimal tempeature of 40$\circ$C and optimal pH of 4.5. The Km for ascorbic acid and pyrophosphate were 119 mM and 11.9 mM, respectively. The addition of 5,5'-dithiobis-(2-nitrobenzoic acid) into the reaction mixture resulted in the reduction of the enzyme activity at 51%. The enzyme also had a phosphatase activity at weakly acidic pH and the Km for ascorbic acid-2-phosphate in phosphatase activity was 7.9 mM.

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