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61.
62.
新型兼具GPX,SOD, CAT活性的水杨醛Schiff碱衍生物的合成 总被引:1,自引:0,他引:1
以5-磺基水杨醛为母体, 经氯甲基化和硒化反应引入催化基团-SeH, 此化合物经空气氧化、Schiff碱反应以及锰螯合反应, 最终得到一种新型的水杨醛Schiff碱类谷胱甘肽过氧化物酶(GPX)模拟物. 测定了该模拟物的红外光谱、核磁共振谱、质谱和抗氧化能力. 此模拟物同时兼具超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性, 水溶性好, 保护线粒体免遭氧化损伤能力强, 具有作为药物前体的潜力. 相似文献
63.
Purification and Characterization of Superoxide Dismutase (SOD) from Camellia Pollen 总被引:1,自引:0,他引:1
HE Xiao-hong WU Min LI Shan-yu FAN Hao CHU Yu-zhuo LIU Lan-ying 《高等学校化学研究》2005,21(5):558-561
A superoxide dismutase( SOD ) was purified to homogeneity from fresh camellia pollen by means of ammonium sulfate precipitation and column chromatography with DEAE-cellulose( DE52 ), Sephadex G-100 and phenyl sepharose^TM 6 Fast Flow columns. Its specific activity could reach to 4034 U/mg protein and it was determined to be Cu/ Zn-SOD according to its different sensitivities to different inhibitors. The molecular weight of the SOD and its subunit were 69500 and 34700, respectively, based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS- PAGE), which implicates that the SOD in camellia pollen is a dimmer composed of two identical subunits. The isoelectric point of the enzyme was determined to be 4. 1 by isoelectric focusing electrophoresis and the N-terminal amino acid was identified to be Gly by the DNS-Cl method. Its α-Helix was also calculated to be approximately 21.8% according to the circular dichroism(CD) spectra. 相似文献
64.
65.
In a popular amperometric superoxide sensor, cytochrome c (Cyt c) is covalently immobilized onto a gold electrode previously covered with a self‐assembled monolayer (SAM) of carboxyl‐terminated alkanethiols. Therefore, a study was carried out to reveal the origins of the current response of such sensors. SAMs made of either 3,3′‐dithiodipropionic acid or 11‐mercaptoundecanoic acid and 11‐mercaptoundecanol were used to immobilize either Cyt c or an inert protein onto gold electrodes. The resulting modified electrodes were comparatively investigated by cyclic voltammetry and calibrated for superoxide detection. The obtained results bring evidence that significant part (>70 %) of the current response of the Cyt c‐modified electrodes to superoxide comes from direct oxidation of superoxide on gold (i.e. does not involve Cyt c). 相似文献
66.
Ping-Chung Kuo Yue-Chiun Li Tsong-Long Hwang Guo-Hao Ma Mei-Lin Yang E-Jian Lee Tian-Shung Wu 《Tetrahedron letters》2014
Linderaggrine A (1) was characterized from the roots of Lindera aggregata and its chemical structure was established by the spectral analysis and chemical transformation. The chemical preparation of 1 and its isomer 2 provide unambiguous evidences for the structural determination of the naturally isolated compound. In addition, the inhibition of superoxide anion generation and elastase release by human neutrophils in response to FMLP/cytochalasin B of these synthetic products had been examined and among the tested compounds, linderaggrine A (1) displayed significant potential against the superoxide anion generation. 相似文献
67.
Yifei Yang Yue Sun Mingzhu Jin Ru Bai Yutong Liu Yingqi Wu Wei Wang Xuewei Feng Siyu Li 《Electroanalysis》2020,32(8):1772-1779
Superoxide dismutase (SOD) plays an important role in nearly all living cells. In this study, SOD imprinted poly(ionic liquid)s (SIPILs) were prepared on the surface of the bare Au electrode modified with nano‐palladium and nano‐gold (Au/nPd/nAu/SIPILs). SIPILs was synthesized with 1‐vinyl‐3‐propyl imidazole sulfonate ionic liquids as functional monomers via electrochemically mediated atom transfer radical polymerization (eATRP) catalyzed by SOD. The Au/nPd/nAu/SIPILs was examined by cyclic voltammetry (CV), scanning electron microscope (SEM), energy‐dispersive spectrometer (EDS) and X‐ray photoelectron spectroscopy (XPS). The Au/nPd/nAu/SIPILs was also used as an electrochemical sensor to determine SOD by differential pulse voltammetry (DPV). Under the optimal conditions, the detection range of SOD was from 1.0×10?8 to 1.0×102 mg L?1 with a limit of detection of 8.90×10?9 mg L?1 (S/N=3). Compared with other methods, the sensor based on SIPILs had the broader linear range and lower detection limit. 相似文献
68.
Paulo Roberto F. Louzada Jr. Marcelo E. Scaramello Clarissa Maya-Monteiro Alex W. M. Rietveld Sérgio T. Ferreira 《Journal of fluorescence》1996,6(4):231-236
Effects of hydrostatic pressure on the fluorescence emission of L-tryptophan, N-acetyl-L-trytophanamide and indole were investigated. An increase in pressure ranging from 1 bar to 2.4 kbar results in reversible red-shifts of the emission of the three fluorophores. The pressure-induced redshift amounts to about 170 cm–1 at 2.4 kbar, and appears related to changes in Stokes shift of the fluorophores caused by pressure effects on the dielectric constant and/or refractive index of the medium. As the pressure range investigated here is the range commonly used in studies of protein subunit association and/or folding, these observations raise the need for caution in interpreting pressure-induced spectral shifts. The significance of these observations to pressure studies of proteins is illustrated by investigation of pressure effects on human Cu,Zn Superoxide dismutase (SOD) and azurin fromPseudomonas aeruginosa. A reversible 170 cm–1 red-shift of the emission of SOD was observed upon pressurization to 2.4 kbar. This might be interpreted as pressure-induced conformational changes of the protein. However, further studies using SOD that had been fully unfolded by guanidine hydrochloride, and fluorescence anisotropy measurements indicated that the observed red-shift was likely due to a direct effect of pressure on the fluorescence of the single tryptophan residue of SOD. Similar pressure-induced red-shifts were also observed for the buried tryptophan residue of azurin or for azurin that had been previously denatured by guanidine hydrochloride. These observations further suggest that the effective dielectric constant of the protein matrix is affected by pressure similarly to water. 相似文献
69.
Formation of superoxide anion radicals (O2·−) induced by 50 kHz ultrasound in argon (Ar)-saturated aqueous solution was studied. Although EPR-spin trapping study with 5,5-dimethyl-1-pyrroline N-oxide (DMPO;100 mM) revealed the formation of DMPO-adducts of hydroxyl radicals (·OH) and hydroperoxy radicals (HO2·; acid form of O2·−) in O2-saturated solution after sonication, no evidence of HO2· was found in Ar-saturated solution. When ferricytochrome c (cytochrome c) in Ar-saturated aqueous solution was sonicated, the reduced form of cytochrome c was observed and 80% of its formation was inhibited by the addition of superoxide dismutase (SOD). Sodium formate enhanced the production of the reduced form of cytochrome c. The % inhibition by SOD for the reduction increased in the order of Xe > Ar > He in accord with the higher temperatures of the cavitation bubbles. These results indicate that the O2·− is formed by directly by the sonolysis of water in the absence of O2 when the temperature of cavitation bubble collapse is sufficiently high. 相似文献
70.
对生命体系中的氧自由基,Spin trapping-ESR方法是公认的特征分析手段[1].然而,对超氧阴离子自由基(O2-·)而言,其自由基加合物稳定性差.对此,人们通过改变硝酮的取代基团,设计出更为有效的O2-·捕获探针[2,3].另外,Zweier研究组[4,5]还应用密度泛函理论研究了影响五元环状硝酮 相似文献