Yeast 14-3-3 proteins participate in the regulation of cell cation homeostasis via interaction with Nha1 alkali-metal-cation/proton antiporter.
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Chiroptical spectra of tetrakis (+)-3-heptafluorobutylrylcamphorate Ln(III) complexes with an encapsulated alkali metal ion: solution structures as revealed by chiroptical spectra.
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Matrix-assisted laser desorption ionization mass spectrometry of maltohexaose and acetylsalicylic acid using alkali metal cation-substituted zeolites.
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Using alkali-metal cation-substituted zeolites and 2,4,6-trihydroxyacetophenone (THAP), which is a typical organic matrix molecule for matrix-assisted laser desorption ionization (MALDI), mass spectrometry has been performed for maltohexaose and acetylsalicylic acid, and the cation-selective ionization of these analytes was achieved. It is found that a complex of cation-substituted zeolite and THAP can be applicable to a compound that is hard to be ionized by a proton adduction in conventional MALDI. (+info)
Characterization of a recombinant thermostable xylanase from hot spring thermophilic Geobacillus sp. TC-W7.
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A xylanase-producing thermophilic strain, Geobacillus sp. TC-W7, was isolated from a hot spring in Yongtai (Fuzhou, China). Subsequently, the xylanase gene that encoded 407 amino acids was cloned and expressed. The recombinant xylanase was purified by GST affinity chromatography and exhibited maximum activity at 75 degrees C and a pH of 8.2. The enzyme was active up to 95 degrees C and showed activity over a wide pH range of 5.2 to 10.2. Additionally, the recombinant xylanase showed high thermostability and pH stability. More than 85% of the enzyme's activity was retained after incubation at 70 degrees C for 90 min at a pH of 8.2. The activity of the recombinant xylanase was enhanced by treatment with 10 mM enzyme inhibitors (DDT, Tween-20, 2-Me, or TritonX-100) and was inhibited by EDTA or PMSF. Its functionality was stable in the presence of Li+, Na+, and K+, but inhibited by Hg2+, Ni2+, Co2+, Cu2+, Zn2+, Pb2+, Fe3+, and Al3+. The functionality of the crude xylanase had similar properties to the recombinant xylanase except for when it was treated with Al2+ or Fe2+. The enzyme might be a promising candidate for various industrial applications such as the biofuel, food, and paper and pulp industries. (+info)
Magnetic instability and pair binding in aromatic hydrocarbon superconductors.
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Effect of metal ions on the hydrolytic and transesterification activities of Candida rugosa lipase.
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In order to study the effect of metal ions on lipase activity, hydrolytic and transesterification activities of Candida rugosa lipase were investigated in presence of alkali (Na(+) and K(+)), alkaline earth (Ca(+)(2) and Ba(+)(2)) and transition (Cr(+)(3), Fe(+)(3), Co(+)(2), Cu(+)(2) and Ni(+)(2)) metal ions. Maximum enhancement in hydrolytic activity of lipase was observed by Ca(+)(2), and in transesterification activity by Cr(+)(3) and Co(+)(2). The kinetics of the lipase catalyzed transesterification (methanolysis and ethanolysis) reactions were also studied, and the activation energies of methanolysis and ethanolysis were reduced from 10.16 and 10.24 kcal mol(-)(1), respectively, to 5.41 and 7.55 kcal mol(-)(1), respectively, when reactions were performed in presence of Co(+)(2). Thus, in lipase catalyzed transesterification Cr(+)(3) or Co(+)(2) could be added to the assay in order to produce the biodiesel in relatively shorter reaction duration. (+info)