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71.
Mugford PF Wagner UG Jiang Y Faber K Kazlauskas RJ 《Angewandte Chemie (International ed. in English)》2008,47(46):8782-8793
One often-cited weakness of biocatalysis is the lack of mirror-image enzymes for the formation of either enantiomer of a product in asymmetric synthesis. Enantiocomplementary enzymes exist as the solution to this problem in nature. These enzyme pairs, which catalyze the same reaction but favor opposite enantiomers, are not mirror-image molecules; however, they contain active sites that are functionally mirror images of one another. To create mirror-image active sites, nature can change the location of the binding site and/or the location of key catalytic groups. In this Minireview, X-ray crystal structures of enantiocomplementary enzymes are surveyed and classified into four groups according to how the mirror-image active sites are formed. 相似文献
72.
Kavitha Telikepalli Király Tamás Matuschke Jannik Schlotter Ildikó Schmidt-Kraepelin Ulrike 《Mathematical Programming》2022,192(1-2):567-595
Mathematical Programming - Let G be a digraph where every node has preferences over its incoming edges. The preferences of a node extend naturally to preferences over branchings, i.e., directed... 相似文献
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Capillary electrochromatography (CEC) was employed as a rapid and high-efficiency method for the isocratic separation of all 20 important phenylthiohydantoin (PTH) amino acids, the end products of Edman degradation during N-terminal protein sequencing. For this purpose, 75 microm ID fused-silica capillaries were packed with standard 3 microm Hypersil octadecyl silica (ODS) particles using a two-step column fabrication process, which represents a fast, reliable and efficient means of producing long-term stable columns. The influence of solvent composition, pH, type of buffer cation, buffer concentration, and temperature on retention behavior of PTH amino acids was investigated. Same-day and day-to-day reproducibility of the retention times (over a period of two months) were found to be better than 3%. When comparing this new technique with traditional reversed phase-high performance liquid chromatography (RP-HPLC) methods applied in automated protein sequenators, CEC shows essentially shorter separation times and superior resolution. 相似文献
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Jens Schmitz Eberhard Heller Ulrike Holzgrabe 《Monatshefte für Chemie / Chemical Monthly》2007,44(6):171-174
By using microwave irradiation bisammonium-and bispyridinium-type allosteric modulators of muscarinic receptors can be obtained
fast and efficiently. 相似文献
77.
Ulrike Tillmann 《K-Theory》1992,6(5):457-463
Karoubi's relative Chern character is constructed as a chain map factoring through Lie algebra chains.This is part of the author's doctoral thesis, Stanford University 1990. 相似文献
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Tanja Vidaković-Koch Tamara Miličić Luka A. Živković Hoon Seng Chan Ulrike Krewer Menka Petkovska 《Current Opinion in Electrochemistry》2021
The nonlinear frequency response analysis (NFRA) can be seen as an extension of electrochemical impedance spectroscopy. NFRA gives a full and detailed representation of the system response and can establish a connection between model parameters and the experimentally observed phenomena. In this article, different theoretical NFRA approaches and the most recent application examples are discussed. A simple electrochemical example is used to showcase the benefits and disadvantages of analyzing the system response by using different approaches. In addition, it was shown how to extract experimental harmonic values and analyze them. 相似文献