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31.
本文利用各种光谱手段在体外研究了各种浓度的Pb2+对菠菜Rubisco活性影响的机制。 结果表明,Rubisco活性随着Pb2+处理浓度的增加而逐渐下降,低浓度Pb2+下Rubisco的动力学常数和最大反应速率分别为1.74 µM 和 0.42 µmol CO2/mg protein∙min,高浓度Pb2+下Rubisco的动力学常数和最大反应速率分别为11.82 µM and 0.28 µmol CO2/mg protein∙min。光谱学分析证实Pb2+可直接结合到Rubisco上, 其结合位点数为1.1个,结合常数分别为8.63×104 和 2.18×105 L/mol。ICP-MS和圆二色谱分析证实Pb2+取代了酶活性中心的Mg2+ 并改变了酶的构象。 相似文献
32.
Yong Nian Ni a b Xue Zhi Zhong a a Department of Chemistry Nanchang University Nanchang China b The Key Laboratory of Food Science of MOE Nanchang University Nanchang China 《中国化学快报》2007,(5)
The binding characteristics of neutral red (NR) with DNA were investigated by fluorescence spectrometry. Chemometrics approach as singular value decomposition (SVD) was used to evaluate the number of spectral species in the drug-DNA binding process, and then the intrinsic binding constant of 1.6 104 in base pairs and the binding site number of 0.97 were obtained from the Scatchard plot. 相似文献
33.
Synthesis and Crystal Structural Characterization of a Thiosemicarbazone Derived from 4-Acylpyrazolone 总被引:1,自引:0,他引:1
LIU Guang-Feia LIU Langa HU Xina JIA Dian-Zenga② YU Kai-Beib a 《结构化学》2006,25(10):1233-1237
1 INTRODUCTION Pyrazol-5-one derivatives form an important class of organic compounds due to their structural che- mistry and biological activities as analgesic, antipy- retic, anti-inflammatory and hyperglycemic agents[1~4]. Even the simplest pyrazol-5-one derivatives like antipyrine and amidopyrine are widely used in anal- gesic medicine[5, 6]. On the other hand, thiosemicar- bazones, especially heterocyclic thiosemicarbazones, have been the subject of extensive investigations be- cause… 相似文献
34.
MAO Shao-Yu a② KANG You-Juna MI Jin-Xiaoa② LI Man-Rongb WEI Zan-Bina WU Xue-Yanb ZHAO Jing-Taib a 《结构化学》2006,25(2):173-179
1 INTRODUCTION Considerable research effort on the heavy metal fluoride glasses like barium, zirconium fluoride and a series of rare-earth fluorozirconate compounds du- ring the last two decades was initiated by the broad optical transmission window of these glasses and thereby the potential for ultralow-loss optical fi- bers[1~10]. The fluorozirconate of alkali metals was first reported in 1938[11], and most of the sodium and potassium fluorozirconates were reported amongthe 1940s and 19… 相似文献
35.
Hai-xia Yang Jin-gang Liu Xiao-juan Zhao Yan-feng Li Lin Fan Shi-yong Yang a School of Chemistry Chemical Engineering Lanzhou University Lanzhou China b Laboratory of Advanced Polymer Materials Institute of Chemistry Chinese Academy of Sciences Beijing China 《高分子科学》2005,(5)
A new type of aromatic tetraamine containing biphenyl moiety in the side chain was synthesized via a modified Chichibabin's reaction.3-Nitro-4-acetamidoacetophenone was reacted with 4-phenyl benzaldehyde in the presence of ammonium acetate to obtain 2,6-bis(3',4'-diaminophenyl)-4-biphenyl pyridine(DPPA).A series of polypyrrolones(PPys) were prepared using tetraamine and various aromatic dianhydrides via a two-step cyclization procedure.All the PPys show excellent high temperature stabilities with the initial decomposition temperatures of 530-549℃ and residual weight ratio of 49%-80% at 750℃ in nitrogen.The polymers exhibit no apparent glass transition temperatures(T_gs)except PPy-1 (T_g=327℃),which is derived from tetraamine DPPA and 2,2-bis[4-(3',4'-dicarboxyphenoxy)-phenyl]propane dianhydride (BPADA).In addition,the polymers have acceptable mechanical properties with the tensile strength of 65-94 MPa.The PPy films show excellent hydrolysis-resistance in alkaline aqueous medium and could maintain most of the properties even after boiling in 10% aqueous sodium hydroxide solution for a week. 相似文献
36.
Photochemical degradation of environmentally persistent perfluorooctanoic acid (PFOA) in the presence of Fe(Ⅲ) 总被引:1,自引:0,他引:1
Yuan Wang~ 《中国化学快报》2008,19(3):371-374
Environmentally persistent and bioaccumulative perfluorooctanic acid (PFOA) was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol/L Fe(Ⅲ), 80% of PFOA with initial concentration of 48μmol/L (20 mg/L) was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe(Ⅲ) initiated degradation of PFOA irradiated with 254 nm UV light. 相似文献
37.
WANG Yong-Jinga b ZHANG Han-Huia b② HUANG Chang-Canga b YU Xiao-Honga SUN Qiao-Zhena SUN Rui-Qinga a 《结构化学》2004,(8)
1 INTRODUCTION As a rich remarkable class of inorganic cluster systems, polyoxometalates continue to be the focus of significant attention in the 21th century because of their various and alluring topologies as well as their unusual physicochemical prope… 相似文献
38.
JIN Fenga b FENG Xiao-Juna TIAN Leia WU Jie-Yinga ZHOU Hong-Pinga TIAN Yu-Penga c a 《结构化学》2005,24(6):645-650
A new compound 1,1‘-bis(3-pyridyl)-propylene(3,7-diformyl-N-ethylphenothiazinyl)ketone (C30H23N3O2S, Mr = 489.4) has been synthesized, and its crystal structure was determined by single-crystal X-ray diffraction method. The crystal is of orthorhombic, space group Ima2 with a = 27.491 (5), b = 11.942(2), c = 7.389(2) A, V = 2425.8(7) A^3, Z = 8, Dc =1.340 g/cm^3,μ = 0,167 mm ^1, F(000) = 1024, the final R = 0.0363 and wR = 0.0869 for 2054 unique reflections with Rint = 0.0254. The structural determination shows that the molecule assumes a butterfly configuration with nearly planar wings. In addition, the electrochemical study indicates that there is a high electronic delocalization in the molecule. 相似文献
39.
1 INTRODUCTION Schiff’s bases are well known ligands representedby many bi-, tri-, tetra-, and hexa-dentate example-es[1], but heptadentate ligands are relatively rare[2, . 3]We have reported a copper complex of tetradentateSchiff’s bases[4]… 相似文献
40.
LI Hao-Honga CHEN Zhi-Ronga② REN Yong-Gang LI Jun-Qiana b HUANG Chang-Canga ZHAO Bina a 《结构化学》2005,(12)
1 INTRODUCTION terested in the unique effects associated with substituents at 4- and 7-positions of the phenan- The coordination chemistry of 1,l0-phenanthroline throline ring. Thus, when phenyl groups are present, and its derivatives has captured the attention of che- the absorptivities of the CT transitions are increased mists for years. The reports on biological importance[1~4], markedly due to the extension of the dipole moment supramolecular chemistry[5], electronic spectra[6], conne… 相似文献