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61.
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Isolation of the lignan secoisolariciresinol diglucoside from flaxseed (Linum usitatissimum L.) by high-speed counter-current chromatography 总被引:1,自引:0,他引:1
High-speed counter-current chromatography was successfully used for the isolation and purification of secoisolariciresinol diglucoside, a bioactive lignan from flaxseed (Linum usitatissimum L.). The solvent system consisted of tert.-butylmethyl ether-n-butanol-acetonitrile-water (1:3:1:5). The purity and identity of the isolated compound was checked by high-performance liquid chromatography analysis in combination with mass spectrometry and NMR measurements. 相似文献
63.
Xiang‐Lei Yang Jianming Liu RobertJ. Skene DuncanE. McRee Paul Schimmel 《Helvetica chimica acta》2003,86(4):1246-1257
Aminoacyl‐tRNA synthetases catalyze the first step of protein synthesis by aminoacylation of tRNAs. Remarkably, biological fragments of two human enzymes – tyrosyl‐tRNA synthetase (TyrRS) and tryptophanyl‐tRNA synthetase – are active cytokines produced by proteolysis or alternative splicing. One is a C‐terminal fragment of TyrRS (C‐TyrRS) that has potent activity for chemotaxis of leukocytes and monocytes and for stimulating production of other cytokines. Significantly, the cytokine activity of C‐TyrRS is absent in the context of the full‐length native protein. Unknown is the mechanism by which domain‐release from the dimeric native protein activates the cytokine. Here, the crystal structure of C‐TyrRS is presented at 2.2 Å resolution. This structure is similar to that of endothelial monocyte‐activating protein II (EMAP‐II), with critical residues of a heptapeptide element important for chemotaxis activity exposed on the first strand of a β‐barrel of the monomeric unit. In contrast, the same residues of C‐TyrRS are buried in an operational model for native TyrRS. Importantly, C‐TyrRS is shown here to be monomeric when released from dimeric native TyrRS. Further analysis suggests that the critical residues are exposed when tRNA is bound. Thus, tRNA binding to native TyrRS may be an additional or alternative way to activate cytokine signaling. 相似文献
64.
An overview is presented of the analytical steps that may be needed to determine the presence of genetically modified organisms (GMOs) or for analysis of GMO-derived produce. The analytical aspects necessary for compliance with labeling regulations are discussed along with bottlenecks that may develop when a plant product or a food sample is analyzed for conformity with current European Union GMO legislation. In addition to sampling and testing, other topics deal with complications that arise from biological and agricultural realities that may influence testing capabilities. The issues presented are intended to serve as elements to examine the different challenges that enforcement laboratories might face. 相似文献
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Herm. Schimmel 《Analytical and bioanalytical chemistry》1906,45(9-10):648-649
68.
Fr. Schimmel 《Fresenius' Journal of Analytical Chemistry》1883,22(1):75
Ohne Zusammenfassung 相似文献
69.
R. Eder E. Schlumpf und Schimmel & Co. 《Fresenius' Journal of Analytical Chemistry》1930,80(5-6):238-239
Ohne Zusammenfassung 相似文献
70.