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  • 1
    Electronic Resource
    Electronic Resource
    Structures of Rare Earth Homodinuclear Macrocyclic Complexes with the Polyamine Polycarboxylic Ligand 1,4,7,10,14,17,20,23-Octaazacyclohexacosane-1,4,7,10,14,17,20,23-octaacetic Acid (H8OHEC) in the Crystal and in Solution (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1735-1743 
    Details
    ISSN: 1434-1948
    Keywords: Crystal structure ; Solution structure ; Homodinuclear lanthanide complexes ; Lanthanides ; Macrocyclic ligands ; Polyamine polycarboxylic acid ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The solid-state structures of the four homodinuclear chelate complexes, [Na2(Y2OHEC)(H2O)2] · 7 H2O · C2H5OH (1), [Na2(Gd2OHEC)(H2O)2] · 12 H2O (2), [Na2(Eu2OHEC)(H2O)2] · 11 H2O (3), and [Cs2(La2OHEC)(H2O)2] · 14 H2O (4) (H8OHEC = 1,4,7,10,14,17,20,23-octaazacyclohexacosane-1,4,7,10,14,17,20,23-octaacetic acid), were determined by X-ray crystal structure analysis. Each lanthanide(III) ion is ninefold coordinated by eight donor atoms of the ligand system and the oxygen atom of one water molecule. The structures are compared with those of DOTA- and TETA-coordinated complexes and the conformation of the OHEC ligand system with that of the parent amine and its dinuclear copper complex. NMR investigations of the diamagnetic complex 1indicate a very similar environment of the lanthanide cations in solution and in the solid state. Low-temperature and variable-temperature 1H-NMR measurements prove the existence of two isomers of 1 (3.5:1 ratio) which undergo conformational processes. The rate constants of these processes were deduced from a complete line shape analysis and were used to determine the activation parameters.Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2005/1999/99081_s.pdf or from the author.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Cell cycle and cyclic AMP-dependent phosphorylation of plasma membrane proteins p14 and p24: Defects in smooth surface transformed cells (1983)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 23 (1983), S. 203-209 
    Details
    ISSN: 0730-2312
    Keywords: cell cycle ; cytoplasmic plasma membrane surface ; control of cell proliferation ; proadipocyte stem cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Two proteins which are localized to the cytoplasmic surface of the plasma membrane, p14 and p24, undergo cyclic AMP-dependent phosphorylation in rapidly growing nontransformed murine embryo cells. In this cell system, growth arrest in the G1 phase of the cell cycle induced by growth factor deprivation is associated with the reversible loss in ability to phosphorylate these substrates. By contrast Simian virus 40 and methylcholanthrene transformed cells show both defective G1 growth control and defects in their ability to phosphorylate p14 and p24 under all tested growth conditions. These data suggested a correlation between defects in the physophorylation of p14 and p24 and defects in the ability of transformed cells to G1 growth arrest. The results of the current studies by contrast show that 3T3 T proadipocytcs which have been transformed by the smooth surface tumorigenesis method show different characteristics. They retain the ability to G1 growth arrest in serum-deficient medium. They show cyclic AMP-dependent phosphorylation of p14 and p24 during exponential growth. They do not, however, down regulate p14 and p24 phosphorylation in association with G1 growth arrest. These observations suggest that neoplastic transformation is not necessarily associated with absolute defects in the ability to phosphorylate p14 and p24. Rather, the results of the current study suggest that the inability to modulate the cyclic AMP-dependent phosphorylation of plasma membrane p14 and p24 proteins during the G1 phase of the cell cycle may be more tightly associated with neoplastic transformation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240230117
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  • 3
    Electronic Resource
    Electronic Resource
    1,4,7,10,13,16,19,22-Octaazacyclotetracosane-1,4,7,10,13,16,19,22-octaacetic Acid (H8OTEC) and 1,4,7,10,14,17,20,23-Octaazacyclohexacosane- 1,4,7,10,14,17,20,23-octaacetic Acid (H8OHEC): Synthesis and Characterization of Two Large Macrocyclic Polyamine Polycarboxylic Ligands and Some of Their Copper(II) and Lanthanide(III) Complexes (1997)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 267-277 
    Details
    ISSN: 0009-2940
    Keywords: Macrocyclic ligands ; Lanthanides ; Copper ; Polyamines ; Polycarboxylic acids ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optimized synthesis of two new macrocyclic polyamine polycarboxylic ligands, 1,4,7,10,14,17,20,23-octaazacyclohexacosane-1,4,7,10,14,17,20,23-octaacetic acid (H8OHEC) (10) and 1,4,7, 10,13,16,19,22-octaazacyclotetracosane-1,4,7,10, 13,16,19,22-octaacetic acid (H8OTEC) (12), is presented. The key step in the synthesis of both is the high yield carboxymethylation of the corresponding macrocyclic amines using tert-butyl bromoacetate followed by acidic hydrolysis of the acetate protecting groups. The molecular structures of the intermediates 1,4,7,10,14,17,20,23-octaazacyclohexacosane (OHEC-amine) (8), and octa-tert-butyl 1,4,7,10,13,16,19,22- octaazacyclotetracosane-1,4,7,10,13,16,19,22-octaacetate (OTEC-ester) (11) are determined by X-ray crystal structure analysis. OHEC-amine 8 reacts with 2 equiv. of CuSO4 yielding the dinuclear complex [Cu2(OHEC-amine)](SO4)2 (13). Complex 13 crystallizes with 16 molecules of water. 13 · 16 H2O contains two copper atoms, which are coordinated in a strongly distorted octahedral fashion by four nitrogen atoms, one oxygen atom from the sulfate dianion and one oxygen atom from a water molecule. The new ligands 10 and 12 are fully characterized by 1D- and 2D-NMR spectroscopy. Both ligands form dinuclear lanthanide(III) chelates (Ln=Y, Sm, Eu, Gd, Yb, Lu), which are stable and highly water soluble. With lanthanum(III) only mononuclear complexes are formed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19971300221
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  • 4
    Electronic Resource
    Electronic Resource
    Topography of protein kinases and phosphoproteins in the plasma membrane of 3T3 cells (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 121 (1984), S. 357-367 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The plasma membrane of 3T3 cells contains at least two different endogenous cyclic AMP-dependent protein kinase systems. One catalyzes the phosphorylation of endogenous protein substrates, i.e., PP24 and PP14, whereas the other catalyzes the phosphorylation of exogenous substrates. In this paper the topography of these cyclic AMP-dependent phosphorylation systems is described. The results show that the kinases which phosphorylate only exogenous substrates are primarily localized to the outer plasma membrane surface whereas the endogenous cyclic AMP-dependent protein kinase and its two endogenous substrates are localized to the cytoplasmic plasma membrane surface. The data also establish that neither the cytoplasmically orientated kinase nor its substrates has a transmembrane orientation even though factors acting on the outer plasma membrane can affect these proteins. This suggests that functional modulation of the cytoplasmically localized cyclic AMP-dependent phosphorylation system can be mediated by a transmembrane regulatory mechanism. The importance of determining the topography of such plasma membrane phosphorylation systems is emphasized by recent studies which show that neoplastic transformation can be mediated at least in part by protein kinases and/or phosphoproteins which are localized on the cytoplasmic surface of the plasma membrane.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041210213
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