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Ratni Saini Olga Kataeva Arndt W. Schmidt Yuqin Wang Anna Meljon William J. Griffiths Hans-Joachim Knölker 《Bioorganic & medicinal chemistry》2013,21(18):5794-5798
Using 3β-hydroxychol-5-en-24-oic acid (4) as starting material, the diastereoisomeric allylic alcohols (24E)-26-hydroxydesmosterol (2) and (24Z)-26-hydroxydesmosterol (3) have been synthesised in six steps with 67% and 12% overall yield, respectively. Both of these isomers are found in newborn mouse brain where sterol synthesis is high. Unlike desmosterol (1), neither of these isomers is a ligand to the liver x receptors and thus represents a novel biological deactivation mechanism avoiding cholesterol synthesis. 相似文献
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Khripach VA Sviridov OV Priadko AG Litvinovskaia RP Drach SV Matveentsev VD Novik TV Mikhaĭlopulo KI Zhabinskiĭ VN Zavadskaia MI Aver'kova MA Drachenova OA Chashchina NM 《Bioorganicheskaia khimiia》2007,33(3):371-378
Brassinosteroids are a new group of phytohormones that are widely distributed in plants and play an important role in the processes of plant growth and development. Physiological concentrations of brassinosteroids in plants are extremely low, and their analysis in organs and tissues is very difficult. This study is devoted to the chemical aspects of elaboration and to bioanalytical parameters of an immunoenzymatic system for quantitative determination of the phytohormones 24-epicastasterone and 24-epibrassinolide. 相似文献
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(24R and 24S)-5β-cholestane-3α,7α,24,25-tetrols were prepared by osmium tetroxide oxidation of 5β-cholest-24-ene-3α,7α-diol. The resulting diastereomeric tetrols were separated by thin-layer chromatography, their purity ascertained by melting point, gas-liquid chromatography and mass spectra and their structural configurations were assigned by molecular rotation measurement and circular dichroism studies. In a similar fashion, the (24R and 24S)-5β-cholestane-3α,24, 25-triols were prepared and their structures identified. 相似文献
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V. A. Khripach O. V. Sviridov A. G. Pryadko R. P. Litvinovskaya S. V. Drach V. D. Matveentsev T. V. Novik K. I. Mikhailopulo V. N. Zhabinskii M. I. Zavadskaya M. A. Aver’kova O. A. Drachenova N. M. Chashchina 《Russian Journal of Bioorganic Chemistry》2007,33(3):347-353
Brassinosteroids are a new group of phytohormones that are widely distributed in plants and play an important role in the processes of plant growth and development. Physiological concentrations of brassinosteroids in plants are extremely low, and their analysis in organs and tissues is very difficult. This study is devoted to the chemical aspects of elaboration and to bioanalytical parameters of an immunoenzymatic system for quantitative determination of the phytohormones 24-epicastasterone and 24-epibrassinolide. 相似文献
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Arabidopsis det2 is defective in the conversion of (24R)-24-methylcholest-4-En-3-one to (24R)-24-methyl-5alpha-cholestan-3-one in brassinosteroid biosynthesis.
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T Noguchi S Fujioka S Takatsuto A Sakurai S Yoshida J Li J Chory 《Plant physiology》1999,120(3):833-840
Previously, we have shown that the Arabidopsis det2 (deetiolated2) mutant is defective in the biosynthesis of brassinosteroids (BR) and that DET2 (a steroid 5alpha-reductase) acts early in the proposed BR biosynthetic pathway. In this paper we present further biochemical characterization of det2. We have undertaken metabolic experiments with 2H-labeled substrates of intermediates involved in the formation of campestanol from campesterol, and quantitative analysis of intermediates in Arabidopsis wild type and det2. The results of these studies indicate the early operating steps of BR biosynthesis as: campesterol --> 4-en-3beta-ol --> 4-en-3-one --> 3-one --> campestanol in Arabidopsis, with det2 deficient in the conversion of 4-en-3-one to 3-one. We have also detected these intermediates in the formation of campestanol from campesterol and their metabolic conversions using cultured cells of Catharanthus roseus. These studies confirmed the biosynthetic sequence of events from campesterol to campestanol as was found in Arabidopsis. As such, the originally proposed biosynthetic pathway should be modified. 相似文献