Xanthomonas maltophilia CBS 897.97 as a source of new 7β- and 7α-hydroxysteroid dehydrogenases and cholylglycine hydrolase: Improved biotransformations of bile acids
摘要:
The paper reports the partial purification and characterization of the 7 beta- and 7 alpha-hydroxysteroid dehydrogenases (HSDH) and cholylglycine hydrolase (CGH), isolated from Xanthomonas maltophilia CBS 897.97. The activity of 7 beta-HSDH and 7 alpha-HSDH in the reduction of the 7-keto bile acids is determined. The affinity of 7 beta-HSDH for bile acids is confirmed by the reduction, on analytical scale, to the corresponding 7 beta-OH derivatives. A crude mixture of 7 alpha- and 7 beta-HSDH, in soluble or immobilized form, is employed in the synthesis, on preparative scale, of ursocholic and ursodeoxycholic acids starting from the corresponding 7 alpha-derivatives. On the other hand, a partially purified 7 beta-HSDH in a double enzyme system, where the couple formate/formate dehydrogenase allows the cofactor recycle, affords 6 alpha-fluoro-3 alpha, 7 beta-dihydroxy-5 beta-cholan-24-oic acid (6-FUDCA) by reduction of the corresponding 7-keto derivative. This compound is not obtainable by microbiological route. The efficient and mild hydrolysis of glycinates and taurinates of bile acids with CGH is also reported. Very promising results are also obtained with bile acid containing raw materials. (c) 2005 Elsevier Inc. All rights reserved.
Highly Chemoselective Reduction of Amides (Primary, Secondary, Tertiary) to Alcohols using SmI<sub>2</sub>/Amine/H<sub>2</sub>O under Mild Conditions
作者:Michal Szostak、Malcolm Spain、Andrew J. Eberhart、David J. Procter
DOI:10.1021/ja412578t
日期:2014.2.12
Highly chemoselective direct reduction of primary, secondary, and tertiary amides to alcohols using SmI2/amine/H2O is reported. The reaction proceeds with C–N bond cleavage in the carbinolamine intermediate, shows excellent functional group tolerance, and delivers the alcohol products in very high yields. The expected C–O cleavage products are not formed under the reaction conditions. The observed
Methylated β-Cyclodextrins: Influence of Degree and Pattern of Substitution on the Thermodynamics of Complexation with Tauro- and Glyco-Conjugated Bile Salts
作者:Christian Schönbeck、Peter Westh、Jens Christian Madsen、Kim Lambertsen Larsen、Lars Wagner Städe、René Holm
DOI:10.1021/la200381f
日期:2011.5.17
cavity entrance, while methylgroups at O2 promote complexation by extending the hydrophobic cavity. Like in the case of 2-hydroxypropylated cyclodextrins, the methyl substituents cause an increased release of ordered water from the hydration shell of the bile salts, resulting in a strong increase in both the enthalpy and the entropy of complexation with increased number of methyl substituents. Due to
Thermodynamics and structure of inclusion compounds of tauro- and glyco-conjugated bile salts and β-cyclodextrin
作者:René Holm、Wei Shi、Rune A. Hartvig、Sune Askjær、Jens Christian Madsen、Peter Westh
DOI:10.1039/b820487j
日期:——
The interaction between natural β-cyclodextrin and bile salts common in rat, dog and man, taurocholate, tauro-β-muricholate, taurodeoxycholate, taurochenodeoxycholate, glycocholate, glycodeoxycholate and glycochenodeoxycholate, was studied using isothermal titration calorimetry, and the structural differences in the interaction were investigated by 1H-ROESY NMR and molecular modeling. The β-cyclodextrin was selected based upon its frequent use in preformulation and drug formulation as oral excipients for the solubilization of drug substances with low aqueous solubility. All the investigated bile salts possessed affinity for the cyclodextrin, though with large variations in the stability constants. The variations in the enthalpic and entropic contributions to the overall Gibbs free energy and consequently the stability constants revealed differences in the binding mode between the investigated bile salts, i.e. the bile salts with a hydroxyl group on C12 interacted differently from the bile salts without this hydroxyl group. These observations were supported by both 1H-ROESY NMR and molecular modeling, which suggested binding on the D-ring in the steroid structure for the former and on the C-ring for the latter bile salts.
采用等温滴定量热法研究了天然δ-环糊精与大鼠、狗和人体内常见的胆盐(牛胆酸盐、牛δ-臼胆酸盐、牛脱氧胆酸盐、牛酚脱氧胆酸盐、甘氨胆酸盐、甘氨脱氧胆酸盐和甘氨苯脱氧胆酸盐)之间的相互作用,并通过 1H-ROESY NMR 和分子建模研究了相互作用中的结构差异。之所以选择δ-环糊精,是因为它经常作为口服辅料用于制剂前和药物制剂中,以增溶水溶性较低的药物物质。所有研究的胆汁盐都与环糊精具有亲和性,但稳定性常数差异较大。总体吉布斯自由能的焓贡献和熵贡献的变化以及由此产生的稳定性常数揭示了所研究胆汁盐之间结合模式的差异,即 C12 上带有羟基的胆汁盐与不带羟基的胆汁盐的相互作用方式不同。这些观察结果得到了 1H-ROESY NMR 和分子建模的支持,前者认为与类固醇结构中的 D 环结合,后者认为与 C 环结合。
Feeding buffers, systems, and methods for in vitro synthesis of biomolecules
申请人:Kudlicki Antoni Wieslaw
公开号:US20060110788A1
公开(公告)日:2006-05-25
Compositions, methods and kits for in vitro systems for synthesis of biomolecules such as polypeptides, are provided herein. Cell extracts that provide enhanced yields of soluble proteins using in vitro protein synthesis methods are provided. The invention also includes methods for producing high yields of proteins by the addition of a feeding solution that includes amino acids and an energy source to an ongoing in vitro synthesis system. The invention also includes methods of using a high-yield in vitro synthesis system to produce large quantities of proteins with incorporated labeled amino acids for analysis by methods such as by NMR. The invention further includes vectors for enhanced production of proteins from nucleic acid templates using in vitro synthesis systems.
Compositions and methods for analyzing biomolecules using mass spectroscopy
申请人:Pope Marshall Robert
公开号:US20060214104A1
公开(公告)日:2006-09-28
Compositions and methods for mass spectroscopy are disclosed. The compositions and methods relate to the analysis of proteins and other biopolymers using mass spectroscopy, particularly matrix-assisted laser desorption time-of-flight mass spectrometry (MALDI-TOF MS).