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131.
Two methods, e.g. initial rate method and thermokinetic reduced extent method were presented for studies on non-competitive
inhibition. Arginase-catalyzed the hydrolysis of L-arginine toL-ornithine and urea and the inhibition of this reaction by sodium fluoride were studied in the absence and presence of exogenous
of Mn2+at 37°C in 40 mM sodium barbiturate-hydrochloric acid buffer solution (pH 7.4). Both methods were successively used to determine
the values of K1. The advances and disadvantages of each method were compared in this paper. Exogenous Mn2+ could result in more sensitivity of arginase to F-1. Since the inhibition of arginase by F-1 depends on the pH values of the reaction system and behave as a non-competitive inhibition, it probably due to its small
volume and high electronic density allow it access to the activity site of the enzyme and replaces of μ-OH2 (or μ-OH) as the bridge ligand with Mn(II, II) cluster. However, further studies are necessary to determine the modes of
interaction of F-1 with bovine liver arginase.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
132.
水合硫酸氢钠催化合成2-乙氧基萘 总被引:2,自引:0,他引:2
以-水合硫酸氢钠为催化剂,β-萘酚和无水乙醇为原料合成了2-乙氧基萘。优化反应条件为:β-萘酚150mmol,无水乙醇900mmol,催化剂2.0g,回流反应时间5h,产率85.5%。 相似文献
133.
Yasuyuki Takeda Chihiro Takagi 《Journal of inclusion phenomena and macrocyclic chemistry》1994,17(1):93-97
The theory is derived to determine the dimer-formation constant,K
2, of a crown ethermetal salt 111 complex in organic solvents of low dielectric constant by solvent extraction. The theoretical predictions are verified experimentally by extraction of sodium picrate (NaA) with 15-crown-5 (15C5) into carbon tetrachloride. All the experiments were conducted at 25°C. The logK
2 value of the Na(15C5)A complex in carbon tetrachloride has been determined to be 4.05±0.11. Moreover, the partition constant of the complex is calculated. 相似文献
134.
A. A. Vedenyapin M. D. Baturova G. I. Ioseliani G. Kh. Areshidze 《Russian Chemical Bulletin》1997,46(1):76-80
The anodic oxidation of the carbon felt Carbonetcalon results in the formation of surface defects which serve as centers of
strong adsorption of PdII, NiII, and CuII ions. The electrochemical reduction of adsorbed ions makes it possible to obtain metallic catalysts, which undergo multiple
redox cycles without loss of metal. The catalysts are characterized by high dispersity of the reduced phase, high adsorption
capacity with respect to hydrogen, and 100% selectivity in hydrogenation of acetophenone.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 81–85, January 1997 相似文献
135.
Conductance data for sodium nitrite, chloride, and acetate in water andN,N-dimethylformamide (DMF)-water mixtures (74.82D42.48) for the concentration range 0.001–0.04N, as well as the densities, viscosities, and dielectric constants of the solvent mixtures at 35°C, are reported. The data have been analyzed by the Fuoss (1975) equation. The existence of a maximum in the viscosity at a 13 mole ratio of DMF and water is indicated. The Walden products for all the three salts pass through a maximum while the equivalent conductances show a minimum with increasing DMF content. The maxima in the Walden product are attributed to the dehydration of ions by the cosolvent (DMF).Part I:Indian J. Chem.
14A, 1015 (1976).Deceased. 相似文献
136.
Effect of bicarbonate ions on the copper passivity and its local breakdown is studied by cyclic voltammetry, Auger spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy. Comparing data for solutions with various sodium bicarbonate concentrations shows copper to undergo pitting in 0.02 M NaHCO3, whereas it remains stably passive in 0.10 M NaHCO3. Independent studies suggest that carbonates play a protective role in stabilization of the oxide-hydroxide passive film on copper. 相似文献
137.
建立了处理双原子分子-表面相互作用的推广的LEPS势.借助推广的LEPS势,系统研究了一氧化碳分子在铂低指数表面吸附的动力学特性,重现了低指数表面的分子吸附热、吸附几何及本征振动等实验数据;鉴定了某些不合理的文献信息,预测了实验尚未探测到的重要信息:预测到Pt(100)表面四重洞位的C-O伸缩振动频率为1 962.60 cm-1;预测到Pt(110)表面吸附态的C-O及C-Pt键长分别为115.1、147 pm. 相似文献
138.
Homogeneous mixed-metal oxides of the general formula (Bi/E/Si)O
x
, where E represents a dopant element (E=Sb, Sn, or Sb/Sn), can be prepared using typical sol-gel processing techniques. Reduction of the in-situ Bi(III) and E ions by hydrogen affords nanocomposites of Bi-Sb, Bi-Sn, or Bi-Sb-Sn widely dispersed throughout the silica xerogel matrix. The materials prepared have high Bi-E metal loading of 52–60 wt. % containing Bi-E alloy nanoclusters of 12–15 nm average diameter. These results demonstrate a convenient method for the production of practical quantities of nanostructured bismuth alloy ceramic composites at high metal content. 相似文献
139.
Patricia M. Nassar Rose M.Z.Georgetto Naal Silvia H. de Pauli João B.S. Bonilha Laura T. Okano Frank H. Quina 《Journal of colloid and interface science》1997,190(2):461
In aqueous solution, the interaction between sodium dodecyl sulfate (SDS) and poly(ethylene glycol) (PEG) results in the formation of small aggregates or clusters of SDS attached to the PEG polymer chain. Selectivity coefficients for exchange of two monovalent (N-methyl-4-cyanopyridinium cation and Tl+) and two divalent (methylviologen cation and Cu2+) counterions at the surface of SDS–PEG clusters, determined employing photophysical techniques, are similar, but not identical, to those for exchange at the surface of SDS micelles in the absence of PEG. The principal factor affecting ion exchange selectivity in SDS–PEG clusters does not appear to be aggregate size or surface charge density but rather the presence of poly(oxyethylene) subunits at the aggregate surface. 相似文献
140.