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Derivatives of Co(II), Ni(II), Cu(II) and Zn(II) with 3′AMP and 2′AMP were synthesized and characterized by IR UV-Vis and fluorescence spectroscopy. There seems to be bonding of the metal ion to the base in all cases. The activation test, using the complexes as allosteric labels, was carried out with rabbit muscle glycogen phosphorylase b, but the enzyme was not activated, confirming that the phosphate group must necessarily be bonded to position 5′ of the ribose in order to activate this enzyme.  相似文献   

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The 2,4,5-tris(2-pyridyl)imidazole ( L ) molecule has been evaluated as a probe for dual sensing of Hg2+ and Cu2+ ions in EtOH/HEPES buffer medium (5 mM, pH = 7.34, 1:1, v/v). Probe L shows a good sensitive and selective turn-off response in the presence of both Hg2+ and Cu2+ ions, which is comprehensible under long UV light. The probe can detect Cu2+ ion in the pH range 3–11 and Hg2+ ion in pH 6–8. The limit of detection for Cu2+ (0.77 μM) is well under the allowable limit prescribed by the United States Environmental Protection Agency. Two metal (Cu2+/Hg2+) ions are needed per L for complete fluorescence quenching. The probe shows marked reversibility on treatment with Na2EDTA, making the protocol more economical for practical purposes. Paper strip coated with the L solution of EtOH can detect the presence of Cu2+ and Hg2+ ions in the sample using visible quenching of the fluorescence intensity. Density functional theory–time-dependent density functional theory (DFT–TDDFT) calculations support experimental observations, and d-orbitals of Cu2+/Hg2+ provide a nonradiative decay pathway. Cell imaging study using HDF and MDA-MB-231 cells also supported the viability of L in detecting Cu2+ and Hg2+ ions in living cells.  相似文献   

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Reaction of the ligand N-methyl-N-((6-pivaloylamido-2-pyridyl)methyl)-N-(2-pyridylethyl)amine (mpppa) with equimolar amounts of [Cu(H2O)6][ClO4]2 or CuCl2 · 2H2O in MeCN afforded mononuclear copper(II) complexes [Cu(mpppa)][ClO4]2 (1) and [Cu(mpppa)Cl2] (2). Crystal structure analysis reveals CuN3O (two pyridyl, an aliphatic amine, and an amide oxygen) coordination in 1 and CuN3Cl2 (two pyridyl, an aliphatic amine, and two chlorides) coordination in 2. Crystal packing diagram of 1 reveals that one of the perchlorate counteranions provides weak coordination to copper(II) centers and in turn the copper(II) centers assume pseudo-six-coordination, generating 1D chain. Notably, one of the copper(II)-coordinated chloride ions in 2 participates in an intramolecular N–H?Cl interaction. Intermolecular C–H?Cl interactions in the solid state generate helical structure. Spectroscopic (IR, UV–Vis, and EPR) and redox properties of the two complexes have been investigated and compared.  相似文献   

6.
Superoxide dismutases (SODs; EC 1.15.1.1) are key enzymes in the cells protection against oxidant agents. Thus, SODs play a major role in the protection of aerobic organisms against oxygen-mediated damages. Three SOD isoforms were previously identified by zymogram staining from Allium sativum bulbs. The purified Cu, Zn-SOD2 shows an antagonist effect to an anticancer drug and alleviate cytotoxicity inside tumor cells lines B16F0 (mouse melanoma cells) and PAE (porcine aortic endothelial cells). To extend the characterization of Allium SODs and their corresponding genes, a proteomic approach was applied involving two-dimensional gel electrophoresis and LC-MS/MS analyses. From peptide sequence data obtained by mass spectrometry and sequences homologies, primers were defined and a cDNA fragment of 456?bp was amplified by RT-PCR. The cDNA nucleotide sequence analysis revealed an open reading frame coding for 152 residues. The deduced amino acid sequence showed high identity (82-87%) with sequences of Cu, Zn-SODs from other plant species. Molecular analysis was achieved by a protein 3D structural model.  相似文献   

7.
The complexes [Cu(DPS)(H2O)Cl2] · H2O (1a) and [{Cu(DPS)Cl}2μ-(Cl)2] (1b) where DPS = Di(2-pyridyl)sulfide have been synthesized and characterized using elemental analysis, thermal analysis (TG/DSC), vibrational and electronic spectroscopies as well as electron paramagnetic resonance (EPR). Additionally, the crystal and molecular structures of both compounds have been determined by X-ray diffraction techniques.  相似文献   

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Pd(II), Cu(II) and Zn(II) complexes (13) based on 4′-(4-(2-(piperidin-1-yl)ethoxy)phenyl)-2,2′:6′,2″-terpyridine were synthesized and characterized by UV, IR, NMR, EPR, HRMS, elemental analyses, and molar conductivity measurements. The cytotoxicity of these complexes against HL-60, BGC-823, KB, Bel-7402, A549, Hela, K562 and MCF-7 cell lines in vitro was measured by MTT method. The DNA binding property of the complexes was evaluated by UV, fluorescence, CD spectroscopies and thermal denaturation. The cytotoxicity of complexes 1 and 3 against all the tested cell lines is better than that of cisplatin. Complexes 1 and 2 exhibit 7- and 4-folds higher cytotoxicity than cisplatin against Bel-7402 cell line. Complex 3 displays the highest cytotoxicity against all the cell lines tested, and shows 7-, 14-, 8-, 11- and 8-folds higher cytotoxicity than cisplatin against Bel-7402, A549, Hela, K562 and MCF-7 cell lines. The complexes bind to DNA via intercalation mode and complex 3 stabilizes the G-quadruplex. The results reveal that all the complexes display high cytotoxicity against all the tested cancer cell lines, and complex 3 is selective for G-quadruplex over duplex DNA.  相似文献   

10.
N-Salicyloyl-N-p-hydroxythiobenzohydrazide (H2STPH) and N-benzoyl-N-thiobenzohydrazide (H2BTBH) and their Co(II), Ni(II), Cu(II) and Zn(II) complexes were prepared and characterized by physicochemical studies. IR and NMR spectral studies imply dibasic tetradentate behaviour of the ligands bonding through `thiolato' sulfur, enolic oxygen and the two hydrazinic nitrogens in a polymeric fashion. The electronic spectra indicate [Ni(STPH)(H2O)2], [Co(STPH)(H2O)2] to be distorted octahedral while [Cu(BTBH)] has a square-planar geometry. In vitro antitumor results of the ligand and the complexes on P-815 (murine mastocytoma) and L-929 (murine fibroblast) indicate that these compounds show significant inhibition of 3H-thymidine and 3H-uridine incorporation in DNA and RNA, respectively, in these tumor cells at dose levels of 1, 2.5 and 5 g cm–3. Antitumor studies suggest that [Cu(BTBH)] has significant dose dependent inhibitory effect on DNA synthesis. In vivo administration of [Cu(BTBH)] and [Ni(STPH)(H2O)2] resulted into prolongation of life span of Dalton's Lymphoma (DL) bearing mice.  相似文献   

11.
Interactions between transition metal ions and polyphenols can result in complexation, redox or polymerization, but the relative importance of these reactions is unclear. The present paper reports results from the reaction of gallic acid (GA) with Cu(II) using electron paramagnetic resonance (EPR) and UV/visible spectroscopy for various relative concentrations and pH values. Reduction of Cu(II) by GA does not occur under strongly acidic or strongly alkaline conditions. Di- or polymerization reactions between Cu(II) and carboxylate groups of GA dominate the results at acidic pH, whereas mononuclear complexes increase in importance at higher pH and GA concentrations. There was no evidence for any redox reaction between Cu(II) and GA and free radical formation from GA at high pH was shown to be the consequence of auto-oxidation, which was inhibited by Cu(II). Serious questions are thus raised about the existence of the frequently assumed redox reactions between Cu(II) and polyphenols.  相似文献   

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β-Glucosidase 2 (GBA2) is an enzyme that cleaves the membrane lipid glucosylceramide into glucose and ceramide. The GBA2 gene is mutated in genetic neurological diseases (hereditary spastic paraplegia and cerebellar ataxia). Pharmacologically, GBA2 is reversibly inhibited by alkylated imino sugars that are in clinical use or are being developed for this purpose. We have addressed the ambiguity surrounding one of the defining characteristics of GBA2, which is its sensitivity to inhibition by conduritol B epoxide (CBE). We found that CBE inhibited GBA2, in vitro and in live cells, in a time-dependent fashion, which is typical for mechanism-based enzyme inactivators. Compared with the well characterized impact of CBE on the lysosomal glucosylceramide-degrading enzyme (glucocerebrosidase, GBA), CBE inactivated GBA2 less efficiently, due to a lower affinity for this enzyme (higher KI) and a lower rate of enzyme inactivation (kinact). In contrast to CBE, N-butyldeoxygalactonojirimycin exclusively inhibited GBA2. Accordingly, we propose to redefine GBA2 activity as the β-glucosidase that is sensitive to inhibition by N-butyldeoxygalactonojirimycin. Revised as such, GBA2 activity 1) was optimal at pH 5.5–6.0; 2) accounted for a much higher proportion of detergent-independent membrane-associated β-glucosidase activity; 3) was more variable among mouse tissues and neuroblastoma and monocyte cell lines; and 4) was more sensitive to inhibition by N-butyldeoxynojirimycin (miglustat, Zavesca®), in comparison with earlier studies. Our evaluation of GBA2 makes it possible to assess its activity more accurately, which will be helpful in analyzing its physiological roles and involvement in disease and in the pharmacological profiling of monosaccharide mimetics.  相似文献   

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《Inorganica chimica acta》1988,147(2):243-250
The acetone complex [Rh(H)2(acetone)2(PPh3)2]- PF6 reacts with bidiazines and 3,6-bis(2′-pyridyl)- pyridazine (dppn) giving the air stable cis-dihydrido rhodium(III) [Rh(H)2(L)(PPh3)2]PF6 complexes. The structure of the dichloromethane solvate of [Rh(H)2(dppn)(PPh3)2]PF6 has been determined by X-ray crystal structure analysis. Crystals are monoclinic, space group P21/a, with a = 18.629(6), b = 15.339(5), c = 17.146(5) Å, β = 101.02(3)° and Z = 4. The structure has been solved from diffractometer data by Patterson and Fourier methods and refined by block-matrix least-squares to R = 0.076 for 6225 observed reflections. In the structure discrete [Rh(H)2(dppn)(PPh3)2]+ cationic complexes, PF6 anions and dichloromethane solvent molecules are present. The Rh atom is octahedrally surrounded by two cis hydride ligands and by two cis nitrogen atoms from a dppn molecule acting as a bidentate chelating ligand through two neighbouring pyridyl and pyridazinyl nitrogen atoms. Two P atoms from PPh3, ligands in trans apical positions complete to octahedral the coordination of Rh.  相似文献   

16.
《Inorganica chimica acta》1988,154(2):215-219
By reacting 2,2′-biimidazole and copper(II) chloride in aqueous HCl we obtained the complex CuCl2(H2bim) as the main product and a compound with stoichiometry Cu1.5Cl3(H2bim)2 as a byproduct. The structure of the latter compound has been determined by X-ray analysis: monoclinic, a= 794.0(3), b=3146.8(6), c=722.9(4) pm, β= 114.2(1)°, space group P21/c. The compound actually contains two species, namely [Cu(H2bim)2]Cl2 and [CuCl2(H2bim)] in a 1:2 molar ratio.  相似文献   

17.
For use as the internal standards in a quantitative analysis of natural jasmonic acid (JA) and methyl jasmonate (JAMe) by gas chromatography-mass spectrometry-selected ion monitoring, (±)-2-(2,3–2H2)JA and its methyl ester, (±)-2-(2,3–2H2)JAMe, were efficiently prepared from 2-(2–pentyl)-2-cyclopentenone through catalytic semi-deuteriogenation of acetylenic intermediates with deuterium gas in pyridine.  相似文献   

18.
A new ligand N-Nicotinoyl-N-o-hydroxythiobenzhydrazide (H2Notbh) forms complexes [Mn(Notbh)(H2O)], [M(Notbh)] [M=Ni(II) Cu(II) and Zn(II)] which were characterized by various physico-chemical techniques. All the metal complexes were observed to inhibit the growth of tumor in vitro, whereas, ligand did not. In vivo administration of these complexes resulted in prolongation of survival of tumor bearing mice. Tumor bearing mice administered with metal complexes showed reversal of tumor growth associated induction of apoptosis in lymphocytes. The paper discusses the possible mechanisms and therapeutic implication of the H2Notbh and its metal complexes in tumor regression and tumor growth associated immunosuppression.  相似文献   

19.
Abstract

2′-C-Cyanomethyl-2′-deoxy-arabinosylcytosine 3 and 2′-C-azidomethyl-2′-deoxy-arabinosylcytosine 4 were synthesized from uridine. The antineoplastic activities of these compounds were evaluated.  相似文献   

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Abstract

Phosphorylation of 1-(2-deoxy-β-D-xylofuranosyl)thymine (1) or 9-(2-deoxy-β-D-xylofuranosyl)adenine (3) with phosphoryl chloride gives the cyclic 3′,5′-phosphates (2 and 4a) but not the 5′-monophosphates 8a or 8b. The latter are obtained by phosphorylation of the 3′-0-benzoylated 2′-deoxy-β-D-xylonucleosides (7a, b) and subsequent base-catalyzed removal of the benzoyl groups. Compound 3, as the parent dA, depurinates in acidic medium, a reaction which is facilitated in the case of the N6-benzoyl derivative 9b and reduced after the introduction of an amidine protecting group. N-Glycosylic bond hydrolysis of 2′-deoxy-β-D-xylofuranosyl nucleosides is enhanced by a factor of two compared to 2′-deoxy-β-D-ribofuranosyl nucleosides.  相似文献   

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