作者机构：
[Cui, YF] Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China.;Hong Kong Univ Sci & Technol, Dept Biochem, Kowloon, Hong Kong, Peoples R China.;Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.
通讯机构：
[Cui, YF] C;Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China.
摘要：
Phytoalexins are low-molecular-weight chemicals that immune systems of plants produce and accumulate in response to infections, especially those of fungal origin. Although their content is not high in plants, yet they have shown unique fungicidal activity and played an important role in the defence system of plants. In searching for novel environmentally benign fungicides with high activity, the structures of flavanone derivatives, one of the most important phytoalexins groups, have been modified via bioisosteric substitution and a series of 2-heteroaryl-4-chromanones were designed and synthesized. They showed good fungicidal activities against rice blast disease, Pyricularia grisea (Sacc). Their IC50 values were tested in vitro and the relationship between structure and fungicidal activity was analyzed quantitatively using a Hansch-Fujita approach. The results showed that hydrophobicity was very important for fungicidal activity and there is apparently an optimum hydrophobic property for the molecules at a log P-ow value of about 2.7. In addition, the results indicated that electronic effects played an important role in binding with the receptor and that the C=O group was probably a electron-accepting site. The quantitative structure-retention correlative equation of the tide compounds was also established. (C) 2002 Society of Chemical Industry.
期刊：
JOURNAL OF AOAC INTERNATIONAL,2002年85(2):456-459 ISSN：1060-3271
通讯作者：
Lu, GH
作者机构：
[Lu, GH] Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.;Wuhan Inst Sci & Technol, Dept Chem & Environm Engn, Wuhan 430074, Peoples R China.;Wuhan Univ, Med Coll Basic Dept, Wuhan 430077, Peoples R China.
通讯机构：
[Lu, GH] C;Cent China Normal Univ, Dept Chem, Wuhan 430079, Peoples R China.
摘要：
In an acid medium, nitrite diazotized with p-rosaniline and then coupled with 8-hydroxyquinoline in a weak alkaline medium produces azo compounds. The azo compounds produce a very sensitive polarographic wave at -0.70 V (versus the saturated calomel electrode). The height of the peak is linear with the concentration of nitrite in the range of 5 x 10(-9) to 5 x 10(-7) g/mL. The detection limit is 3 x 10(-9) g/mL. The electrochemical characteristics of the polarographic wave are also discussed. The method was used to determine nitrite in sausage. The results agree well with those obtained by spectrophotometry.
摘要：
The binuclear structure of Fe2(DTPB)(μ-O)(μ-Ac)CI(BF4)2 (DTPB = 1,1,4,7,7-penta (2′-benzimidazol-2-ylmethyl)-triazaheptane, Ac = acetate) was characterized by UV-visible absorption and infrared spectra and NMR and ESR. The binding interaction of DNA with the diiron complex was examined spectroscopically. Supercoiled and linear DNA hydrolytic cleavage by the diiron complex is supported by the evidence from anaerobic reactions, free radical quenching, high performance liquid chromatography experiments, and enzymatic manipulation such as T4 ligase ligation, 5′-32P end-labeling, and footprinting analysis. The estimation of rate for the supercooiled DNA double strand cleavage shows one of the largest known rate enhancement factors, ∼1010 against DNA. Moreover, the DNA hydrolysis chemistry needs no coreactant such as hydrogen peroxide. The poor sequence-specific DNA cleavage indicated by the restriction analysis of the pBR322 DNA linearized by the diiron complex might be due to the diiron complex bound to DNA by a coordination of its two ferric ions to the DNA phosphate oxygens, as suggested by spectral characterizations. The hydrolysis chemistry for a variety of binuclear metal complexes including Fe2(DTPB)-(μ-O)(μ-Ac)CI(BF4)2 is compared. It is established that the dominant factors for the DNA hydrolysis activities of the binuclear metal complexes are the μ-oxo bridge, labile and anionic ligands, and open coordination site(s). Concerning the hydrolytic mechanisms, the diiron complex Fe2(DTPB)(μ-O)(μ-Ac)CI(BF4)2 might share many points in common with the native purple acid phosphatases.
期刊：
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY,2001年123(12):2835-2838 ISSN：0002-7863
通讯作者：
Zhan, CG
作者机构：
[Zhan, CG] Cent China Normal Univ, Dept Chem, Wuhan 430070, Peoples R China.;Columbia Univ Coll Phys & Surg, Dept Med, New York, NY 10032 USA.;Pacific NW Natl Lab, Richland, WA 99352 USA.
通讯机构：
[Zhan, CG] C;Cent China Normal Univ, Dept Chem, Wuhan 430070, Peoples R China.
摘要：
Phosphodiesterases are clinical targets for a variety of biological disorders, because this superfamily of enzymes regulates the intracellular concentration of cyclic nucleotides that serve as the second messengers playing a critical role in a variety of physiological processes. Understanding the structure and mechanism of a phosphodiesterase will provide a solid basis for rational design of the more efficient therapeutics. Although a three-dimensional X-ray crystal structure of the catalytic domain of human phosphodiesterase 4B2B was recently reported, it is uncertain whether a critical bridging ligand in the active site is a water molecule or a hydroxide ion. The identity of this bridging ligand is theoretically determined by performing first-principles quantum chemical calculations on models of the active site. All the results obtained indicate that this critical bridging ligand in the active site of the reported X-ray crystal structure is a hydroxide ion, rather than a water molecule, expected to serve as the nucleophile to initialize the catalytic degradation of the intracellular second messengers.
关键词：
surface-enhanced Raman spectra;anticancer model drugs;N-D-glucosamine;beta-naphthaldehyde and glycine
摘要：
Copper(II), zinc(II), cobalt(II) and cobalt(III) complexes of N-D-glucosamine β-naphthaldehyde (C<inf>17</inf>H<inf>19</inf>O<inf>6</inf>N, NG) and glycine were synthesized. The four novel metal complexes, Cu(II)C<inf>19</inf>H<inf>28</inf>O<inf>11</inf>N<inf>2</inf>(CuGNG), Zn(II)C<inf>19</inf>H<inf>24</inf>O<inf>9</inf>N<inf>2</inf>(ZnGNG), Co(II)C<inf>19</inf>H<inf>28</inf>O<inf>11</inf>N<inf>2</inf>(Co(II)GNG) and Co(III)C<inf>21</inf>H<inf>29</inf>O<inf>12</inf>N<inf>2</inf>(Co(III)GNG) were characterized by means of infrared (IR), electronic absorption spectroscopy and NMR etc. The surface-enhanced Raman spectra of the four complexes and their interaction with DNA were studied. By comparison of the surface-enhanced Raman spectra (SERS), the information of the four complexes' SER active sites and adsorption orientation were obtained. Combined with fluorescence spectra of Ethidium bromide (EthBr) DNA system, we concluded that none of the four complexes intercalate into DNA and that the presence of the glycine ligand lowered the anticancer activity of NG series complexes.
摘要：
The binding site of Fe3+ in the purine base of adenosine 5'-triphosphate (ATP) was studied by nuclear magnetic resonance (NMR). The NMR relaxation rates (R-1) of H-1 and P-31 in ATP solutions free of and containing ferric ions were measured in the pH range of 3-10. It was found that Fe3+ selectively enhanced the relaxation rate of protons. In the presence of Fe3+, the R-1 of H2 was much bigger than that of H8 at a lower pH (3-4.5), while at a higher pH (5.5-7.5) the R-1 of H8 was more enhanced than H2. At a pH of around 5, both H2 and H8, as well as all three phosphorous, showed a sudden jump in R-1. When pH>8, Fe3+ failed to show appreciable enhancement of R-1 to all protons and phosphorous. The quantitative data of relaxation rate enhancements suggest that the binding site of Fe in ATP is strongly dependent on pH. At lower pH values, Fe3+ binds N1 but at higher pH it binds to N7. When pH is around 5, the whole purine base donates the aromatic pi -electrons to the ferric ion, forming a ferrocene-like complex, while when pH>8, ATP could not form complexes with Fe3+. (C) 2001 Elsevier Science B.V. All rights reserved. [References: 18]
摘要：
The reactions between Laccase (extracted from China lacquer of Rhus vernicifera) and various substrates (3,4-Dihydroxybenzaldehyde, Guaiacol, Pyrogallol, Gallic acid) have been studied using LKB-2107 batch microcalorimetry system. Based on calorimetry, a new method has been proposed. Laccase activity and the Michaelis constant K-m have been determined simultaneously by this method. The method is simple, sample-saving, and valid for a wider range of substrate concentrations. Furthermore, it can be extended for assaying other enzymes catalyzing reactions using this method. (C) 2000 Elsevier Science B.V. All rights reserved.
摘要：
A variety of copper complexes with different structural features have been shown to bind double-helical DNA with binding constants of 10~4-10~7 M~(-1) and to promote double-strand DNA damage upon reductant/H_2O_2 activation. The interaction of the Cu complex with DNA results in hyperchromism and shifts to longer wavelengths of the strongest transitions in the Cu complexes, as well as striking hypochromism or hyperchromism of DNA absorption at 260nm. In the presence of DMPO as the spin trap, the solution of each copper complex exhibits typical four-line ESR spectra of the hydroxyl radical by adding 2-mercaptoethanol and H_2O_2 to the solution. Quantitation by 2-deoxy-D-ribose shows that the competence of hydroxyl radical generation by the copper complexes upon reductant and H_2O_2 activation decreases in order, that is , Cu(HTCD)~(2+) approx Cu(Im)_4Cl_2 approx Cu(IDB)(NO_3)_2 > Cu(IDB)Cl_2 > Cu(IDBt)Cl_2. The copper complex-mediated hydroxyl radical, a powerful oxidant that attacks the adjacent DNA, is responsible for the DNA oxidative damage. The copper complex-mediated hydroxyl radical, a powerful oxidant that attacks the adjacent DNA, is responsible for the DNA oxidative damage. The #lambda#DNA damage chemistry illustrates that the competence and selectivity of double-strand #lambda#DNA damage by the copper complexes are dependent on their geometric structures and types of ligands. The decreasing order of the DNA damage capacity by the present complexes is Cu(Im)_4Cl_2 approx Cu(IDB)-(NO_3)_2 > Cu(HTCD)~(2+) > Cu(IDBt)Cl_2 > Cu(IDB)Cl_2.
作者机构：
[Zeng Y.; 胡继明] Dept. of Anal.-Measurement Science, Wuhan University, 430012 Wuhan, China;[乐芝凤; 沈昊宇] Department of Chemistry, Huazhong Normal University, 430070 Wuhan, China;[陈建] Center of Analysis and Measurement, Zhongshan University, 510275 Guangzhou, China;Central China Normal University, China;Department of Chemistry, Wuhan University, China
通讯机构：
[Hu, J.] D;Dept. of Anal.-Measurement Science, , 430012 Wuhan, China
关键词：
D－氨基葡萄糖甘氨酸混配金属配合物;表面增强喇曼光谱
摘要：
研究了四种D-氨基葡萄糖甘氨酸混配金属配合物的表面增强喇曼光谱(SERS), 发现它们在银胶上的吸附方式基本相同, 因而SERS光谱也基本相似, 并用SERS光谱研究了它们与DNA的相互作用, 发现这四种化合物与DNA的作用能力有很大不同, Co (Ⅲ) GluG是值得进一步研究的可能抗癌药物。(图2表1参7)。
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS,1993年1142(1-2):83-87 ISSN：0005-2728
通讯作者：
XU, JX
作者机构：
HUAZHANG NORMAL UNIV,INST ORGAN SYNTH,WUTTAN,PEOPLES R CHINA.;ZHONSHAN UNIV,DEPT CHEM,CANTON,PEOPLES R CHINA.;[XU, JX] CHINESE ACAD SCI,INST BIOPHYS,BEIJING,PEOPLES R CHINA.
通讯机构：
[XU, JX] C;CHINESE ACAD SCI,INST BIOPHYS,BEIJING,PEOPLES R CHINA.
关键词：
3-Nitrosalicyl N-alkylamide;Antimycin A;Inhibitory site;QH2:cytochrome c reductase
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS,1991年1057(3):373-376 ISSN：0005-2728
通讯作者：
Xu, J.-x.
作者机构：
ACAD SINICA,INST BIOPHYS,BEIJING 50052728,PEOPLES R CHINA.;HUAZHONG NORMAL UNIV,INST ORGAN SYNTH,WUHAN,PEOPLES R CHINA.;ZHONGSHAN UNIV,DEPT CHEM,GUANGZHOU,PEOPLES R CHINA.;[GU, LQ] Department of Chemistry, Zhongshan University, Guanzhou (China), China;[LIU, C; XU, JX] Institute of Biophysics, Academia Sinica, Beijing (China), China
关键词：
2,6-dicholoroindophenol;2-thenoyl-trifluoroacetone;3-Nitrosalicyl-N-alkylamide;DCIP;Enzyme inhibition;heart muscle preparation;HMP;Q2;Q2H2;Q2H2-cytochrome c reductase;QCR;QPs;Respiratory chain;SCR;SDH;SQR;succinate dehydrogenase;succinate-cytochrome c reductase;Succinate-ubiquinone reductase;succinate-ubiquinone reductase;TTFA;ubiquinol;ubiquinone;ubiquinone-binding protein in SQR
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS,1986年851(3):469-474 ISSN：0005-2728
通讯作者：
Chen, M.
作者机构：
CHINESE ACAD SCI,INST BIOPHYS,BEIJING,PEOPLES R CHINA.;CENT CHINA NORMAL UNIV,DEPT CHEM,WUHAN,PEOPLES R CHINA.;[GU, LQ; LIU, BL] Department of Chemistry, Central China Normal University, Wuhan, China;[ZHU, QS; CHEN, M] Institute of Biophysics, Academia Sinica, Beijing, China
通讯机构：
[Chen, M.] I;Institute of Biophysics, Academia Sinica, Beijing, China
关键词：
(Pig-heart mitochondria);Cytochrome bc1 complex;Plastoquinone;Respiratory chain;Succinate:cytochrome c reductase;Ubiquinone
