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Hyoscyamine 6β-hydroxylase (H6H; EC 1.14.11.11), an important enzyme in the biosynthesis of tropane alkaloids, catalyzes the hydroxylation of hyoscyamine to give 6β-hydroxyhyoscyamine and its epoxidation in the biosynthetic pathway leading to scopolamine. Datura metel produces scopolamine as the predominant tropane alkaloid. The cDNA encoding H6H from D. metel (DmH6H) was cloned, heterologously expressed and biochemically characterized. The purified recombinant His-tagged H6H from D. metel (DmrH6H) was capable of converting hyoscyamine to scopolamine. The functionally expressed DmrH6H was confirmed by HPLC and ESI-MS verification of the products, 6β-hydroxyhyoscyamine and its derivative, scopolamine; the DmrH6H epoxidase activity was low compared to the hydroxylase activity. The Km values for both the substrates, hyoscyamine and 2-oxoglutarate, were 50 μM each. The CD (circular dichroism) spectrum of the DmrH6H indicated a preponderance of α-helicity in the secondary structure. From the fluorescence studies, Stern–Volmer constants for hyoscyamine and 2-oxoglutarate were found to be 0.14 M?1 and 0.56 M?1, respectively. These data suggested that the binding of the substrates, hyoscyamine and 2-oxoglutarate, to the enzyme induced significant conformational changes. 相似文献
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A New Klebsiella planticola Strain (Cd-1) Grows Anaerobically at High Cadmium Concentrations and Precipitates Cadmium Sulfide 下载免费PDF全文
Pramod K. Sharma David L. Balkwill Anatoly Frenkel Murthy A. Vairavamurthy 《Applied microbiology》2000,66(7):3083-3087
Heavy metal resistance by bacteria is a topic of much importance to the bioremediation of contaminated soils and sediments. We report here the isolation of a highly cadmium-resistant Klebsiella planticola strain, Cd-1, from reducing salt marsh sediments. The strain grows in up to 15 mM CdCl2 under a wide range of NaCl concentrations and at acidic or neutral pH. In growth medium amended with thiosulfate, it precipitated significant amounts of cadmium sulfide (CdS), as confirmed by x-absorption spectroscopy. In comparison with various other strains tested, Cd-1 is superior for precipitating CdS in cultures containing thiosulfate. Thus, our results suggest that Cd-1 is a good candidate for the accelerated bioremediation of systems contaminated by high levels of cadmium. 相似文献
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Mukund S. Chorghade Derek A. Dezaro David R. Hill Elaine C. Lee Richard J. Pariza
Jan V. Andersen
Kristian T. HansenDavid H. Dolphin
《Bioorganic & medicinal chemistry letters》1994,4(24):2867-2870Certain synthetic metalloporphyrins have been shown to mimic the in vivo metabolism of some pharmaceuticals. Oxidation, hydroxylation and N-demethylation yielded synthetic metabolites. If found to be general, this lays the foundation of a predictive basis to optimize analog desing of inhibitors with reduced oxidative reactivity, to determine the proclivity of drugs to form biological active metabolites, and provides a convenient methodology for their preparation.
Certain Synthetic metalloporphyrins have been shown to mimic the in vivo metabolism of some pharmaceuticals. Oxidation. hydroxylation and N-demethylation yielded synthetic metabolites. If found to be general, this lays the foundation of a predictive basis to optimize analog design of inhibitors with reduced oxidative reactivity, to determine the proclivity of drugs to form biologically active metabolites, and provides a convenient methodology for their preparation. 相似文献
147.
Pandey Pramod K. Biswas Sagor Vaddella Venkata K. Soupir Michelle L. 《Bioprocess and biosystems engineering》2018,41(6):887-887
Bioprocess and Biosystems Engineering - Escherichia coli persistence kinetics in dairy manure at moderate, mesophilic, and thermophilic temperatures. 相似文献
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Purification of Avian Myeloblastosis Virus DNA Polymerase by Affinity Chromatography on Polycytidylate-Agarose 总被引:9,自引:5,他引:4
Polycytidylic acid [poly(rC)] covalently linked to cyanogen bromide-activated agarose is an effective affinity matrix for the RNA-dependent DNA polymerase from avian myeloblastosis virus. Poly(rC)-agarose is capable of binding large quantities of avian myeloblastosis DNA polymerase, which is then eluted by using a linear KCl gradient of increasing concentration. The DNA polymerase isolated from crude, detergent-disrupted virions by a single pass through columns of poly(rC)-agarose appears nearly homogeneous (approximately 90% pure) as determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. Complete recovery of input enzymatic activity was obtained. Results suggest that polyribonucleotide columns may provide a high-yield, rapid method for the purification of oncornaviral DNA polymerase. 相似文献
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Nirogi RV Kambhampati R Kothmirkar P Konda J Bandyala TR Gudla P Arepalli S Gangadasari NP Shinde AK Deshpande AD Dwarampudi A Chindhe AK Dubey PK 《Journal of enzyme inhibition and medicinal chemistry》2012,27(3):443-450
5-Hydroxytryptamine 6 receptors (5-HT(6)R) are being perceived as the possible target for treatment of cognitive disorders as well as obesity. The present article deals with the design, synthesis, in vitro binding and structure-activity relationship of a novel series of tetracyclic tryptamines with the rigidized N-arylsulphonyl, N-arylcarbonyl and N-benzyl substituents as 5-HT(6) receptor ligands. The chiral sulphonyl derivatives 15a and 17a showed high affinity at 5-HT(6)R with the K(i) of 23.4 and 20.5?nM, respectively. The lead compound from the series 15a has acceptable ADME properties, adequate brain penetration and is active in animal models of cognition like Novel Object Recognition Task (NORT) and water maze. 相似文献