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61.
We have prepared an l-tyrosine derivative bearing a d-threo ketose moiety by a convenient chemoenzymatic route. This compound is of potential interest for developing stereospecific assays for enzymes catalyzing C-C bond cleavage such as transketolase. We showed in vitro by analytical studies (LC/MS and 31P NMR) that this compound can release l-tyrosine in the presence of wild type TK extract and bovine serum albumin. This assay is the first step towards a mutant TK selection test that could be developed for yeast cells auxotrophic for l-tyrosine. 相似文献
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Philippe Franck Beáta Dajka-Halász Katrien Monsieurs Bert U.W. Maes 《Tetrahedron》2008,64(26):6030-6037
Pd-catalyzed cyclodehydrohalogenation involving oxidative addition of aromatic C-Br or activated azaheteroaromatic C-Cl bonds and C(sp2)-H activation have been investigated at high reaction temperatures (180-200 °C). This allowed the fast (10-30 min) synthesis of a variety of azaheteroaromatic ring systems (dibenzo[f,h]phthalazine, dibenzo[f,h]cinnoline, benzofuro[2,3-d]pyridazine, 5H-pyridazino[4,5-b]indole, 7H-indolo[2,3-c]quinoline and 5H-δ-carboline) in moderate to good yields. 相似文献
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Cláudia M. Morais Valérie Montouillout Michael Deschamps Dinu Iuga Franck Fayon Filipe A. A. Paz João Rocha Christian Fernandez Dominique Massiot 《Magnetic resonance in chemistry : MRC》2009,47(11):942-947
From one‐ to two‐ and three‐dimensional MAS NMR solid‐state experiments involving 31P and 27Al, we show that the structure of microporous alumino‐phosphate AlPO4‐40 contains at least four times more sites than expected, and we attribute two types of AlIV sites. The newly described 27Al‐31P MQ‐HMQC opens new possibilities of describing details of three‐dimensional bounded networks. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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This study is in keeping with the general pattern of dynamical simulations of a set of rigid three-dimensional bodies submitted to unilateral contact constraints with dry friction. An exact formulation (respecting the contact and friction laws) of the problem of predicting the system accelerations and the contact status, in further evolution is proposed. A numerical treatment of this kind of nonlinear problem is presented. This approach is applied to a simple multi-contact example, and yields results in agreement with those of analytical and numerical type, known for this example. To cite this article: C. Le Saux et al., C. R. Mecanique 331 (2003). 相似文献
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The study of the interaction of anticancer drugs with mammalian cells in vitro is important to elucidate the mechanisms of action of the drug on its biological targets. In this context, Raman spectroscopy is a potential candidate for high throughput, non-invasive analysis. To explore this potential, the interaction of cis-diamminedichloroplatinum(II) (cisplatin) with a human lung adenocarcinoma cell line (A549) was investigated using Raman microspectroscopy. The results were correlated with parallel measurements from the MTT cytotoxicity assay, which yielded an IC(50) value of 1.2 ± 0.2 μM. To further confirm the spectral results, Raman spectra were also acquired from DNA extracted from A549 cells exposed to cisplatin and from unexposed controls. Partial least squares (PLS) multivariate regression and PLS Jackknifing were employed to highlight spectral regions which varied in a statistically significant manner with exposure to cisplatin and with the resultant changes in cellular physiology measured by the MTT assay. The results demonstrate the potential of the cellular Raman spectrum to non-invasively elucidate spectral changes that have their origin either in the biochemical interaction of external agents with the cell or its physiological response, allowing the prediction of the cellular response and the identification of the origin of the chemotherapeutic response at a molecular level in the cell. 相似文献