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631.
Responsibility of physicians to society 总被引:1,自引:0,他引:1
R Nader 《Federation proceedings》1972,31(6):1578-1581
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J F de Sousa Júnior H B Nader C P Dietrich 《The Journal of biological chemistry》1990,265(33):20150-20155
A sulfatase acting upon chondroitin sulfate polymers, free of beta-glucuronidase and beta-N-acetylhexosaminidases, was isolated from extracts of the mollusc Anomalocardia brasiliana. The enzyme totally desulfates both chondroitin 4- and 6-sulfates without concomitant depolymerization of the compounds. It has no activity upon heparan sulfate, heparin, dermatan sulfate, and chondroitin sulfate disaccharides. It shows a pH of 5.0 and a temperature of 37 degrees C for optimum activity with a Km of 4 x 10(-5) M. The sulfatase is inhibited by sulfate and phosphate ions and HgCl2. The latter inhibition is reverted by sodium tetrathionate. Contrary to the sulfatases described so far the enzyme is activated by the lactone of D-saccharic acid when in the presence of beta-glucuronidase and beta-N-acetylgalactosaminidase. Several experiments indicate that the sulfatase is the first enzyme in the sequential degradation of chondroitin sulfate in the mollusc. This differs from the pathway of degradation of this compound in vertebrates and bacteria. 相似文献
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An inverse relationship between heparin content and antibody response in genetically selected mice. Sex effect and evidence of a polygenic control for skin heparin concentration 下载免费PDF全文
The heparin content of genetically selected mice with high and low antibody response to bacterial antigens is reported. An inverse relationship between antibody titres and concentration of heparin was observed for both male and female mice. The lower-antibody-responder line contains twice as much heparin as the higher-responder ones. Furthermore, the female mice also contained twice as much heparin as the male mice. Genetic analysis of the parental and interline hybrids has shown a partial dominance for the character 'heparin content' in favour of the high-heparin phenotype and this character appears to be subjected to polygenic control. The possible biological role of heparin and/or mast cells in the surveillance of the organism against some pathogens is discussed in the light of these and other findings. 相似文献
636.
Helena B. Nader Helio K. Takahashi Jorge A. Guimares Carl P. Dietrich Pietro Bianchini Bruna Ozima 《International journal of biological macromolecules》1981,3(6):356-360
A comparative study of heparin fractions obtained by affinity chromatography, electrofocusing, selective barium precipitation, polyacrylamide and agarose gel electrophoresis is reported. It is concluded that commercial heparin preparations are heterogeneous, containing at least 120 components which differ in molecular weight, in degree of affinity for antithrombin, and in their distribution in monomeric and dimeric forms. High anticoagulant activity for some heparin fractions was obtained by most of the methods used. 相似文献
637.
Abolfazl Barzegar Ali Akbar Moosavi‐Movahedi Karim Mahnam Homayoon Bahrami Nader Sheibani 《Journal of peptide science》2008,14(11):1173-1182
The nanoscale peptide YSGVCHTDLHAWHGDWPLPVK exhibits molecular chaperone activity and prevents protein aggregation under chemical and/or thermal stress. Here, His mutations of this peptide and their impact on chaperone activity were evaluated using theoretical techniques. Molecular dynamic (MD) simulations with simulated annealing (SA) of different mutant nanopeptides were employed to determine the contribution of the scaffolding His residues (H45, H49, H52), when mutated to Pro, on chaperone action in vitro. The in silico mutations of His residues to Pro (H45P, H49P, H52P) revealed loss of secondary ordered strand structure. However, a small part of the strand conformation was formed in the middle region of the native chaperone peptide. The His‐to‐Pro mutations resulted in decreased gyration radius (Rg) values and surface accessibility of the mutant peptides under the simulation times. The invariant dihedral angle (ϕ) values and the disrupting effects of the Pro residues indicated the coil conformation of mutant peptides. The failure of the chaperone‐like action in the Pro mutant peptides was consistent with their decreased effective accessible surfaces. The high variation of Φ value for His residues in native chaperone peptide leads to high flexibility, such as a minichaperone acting as a nanomachine at the molecular level. Our findings demonstrate that the peptide strand conformation motif with high flexibility at nanoscale is critical for chaperone activity. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
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Haddad Isabella Veríssimo Nader de Sá-Haiad Bárbara de Santiago-Fernandes Lygia Dolores Ribeiro Machado Silvia Rodrigues 《Protoplasma》2019,256(6):1667-1680
Protoplasma - Reproduction in flowering plants is closely related to the megagametophyte, since the megagametophyte is involved in pollen tube reception and contains the two female... 相似文献