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1.
The desulfurization activity of the resting cells of Gordona sp. CYKS1 was strongly depended on harvest time and the highest value when the cells had been harvested in the early growth phase (0.12 mg sulfur g–1 cell–1 h–1). For the model oil, hexadecane containing dibenzothiophene, the specific desulfurization rate decreased as the reaction proceeded. Both the specific and the volumetric desulfurization rates were not significantly affected by the aqueous-to-oil phase ratio. The diesel oils, light gas oil and a middle distillate unit feed were desulfurized at higher rates (ca. 0.34 mg sulfur g–1 cell–1 h–1) than the model oil (0.12 mg sulfur g–1 cell–1 h–1). 相似文献
2.
Gad Avigad Priscilla J. Bohrer 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,798(3):317-324
6-Phosphofructo-2-kinase (ATP: D-fructose-6-phosphate-2-phosphotransferase) and D-fructose-2,6-bisphosphatase activities have been found in extracts prepared from etiolated mung bean seedlings. The activity of 6-phosphofructo-2-kinase exhibits a sigmoidal shape in response to changes in concentrations of both substrates, D-fructose 6-phosphate and ATP (S0.5 values of 1.8 and 1.2 mM, respectively). Inorganic orthophosphate (Pi) has a strong stimulating effect on the 2-kinase activity (A0.5 at about 2 mM), moderately increasing the Vmax and modifying the response into hyperbolic curves with Km values of 0.4 and 0.2 mM for fructose 6-phosphate and ATP, respectively. 3-Phosphoglycerate (I0.5 about 0.15 mM) partially inhibited the kinase activity by counteracting the Pi activation. In contrast, the activity of D-fructose-2,6-bisphosphatase (Km 0.38 mM) is strongly inhibited by Pi (I0.5 0.8 mM) lowering its affinity to fructose-2,6-P2 (Km 1.4 mM). 3-Phosphoglycerate activites the enzyme (A0.5 at about 0.3 mM) without causing a significant change in its Km for fructose-2,6-P2. The activities of both of these enzymes in relationship to the metabolic role of D-fructose 2,6-bisphosphate in the germinating seed is discussed. 相似文献
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The biologically important pyridoxinato(1−) ligand (anionic vitamin B6) shows the rare phenolate-hydroxymethyl chelation plus bridging mode through the pyridine-nitrogen atom towards zinc(II) to give the one-dimensional (1D) coordination polymer {(acetato-κO)-aqua-μ-[2-methyl-3-oxy-4,5-di(hydroxymethyl)pyridine-κN:O,O′]zinc(II)}·monohydrate with polar packing of adjacent chains along the polar c axis (in space group Pc) through strong inter-chain hydrogen bonding. 相似文献
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From three Fouquieria sp. 12 iridoid glucosides were isolated and identified. Eight of these were structurally related to galioside (monotropein methylester), while four were hydroxy substitution products of deoxyloganin. In three cases the glucoside occurred together with the corresponding 10-O-acetate. 相似文献
8.
Cynthia L. Deitrick Richard E. Katholi David J. Huddleston Kathy Hardiek Lucienne Burrus 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2001,751(2)
Vitamin B6, measured as pyridoxal 5′-phosphate (PLP), is a co-enzyme in the transsulfuration pathway of homocysteine metabolism. Since depletion of PLP has been suggested as an independent risk factor for coronary artery disease, PLP is frequently measured to guide patient care. By a change and utilization of an Aquasil C18 column and the addition of an acetonitrile clean-up gradient to the potassium phosphate, with sodium perchlorate and bisulfite buffer between samples we report the modification of a previously described method for analysis of PLP. The result is a more practical, efficient, reliable and robust method for daily clinical use. We also determined and report that it is critical to protect freshly prepared standard PLP samples from light exposure during assay preparation. 相似文献
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S. L. GLOCKLING FLS G. W. BEAKES 《Botanical journal of the Linnean Society. Linnean Society of London》2001,136(3):329-338
Two new species of Haptoglossa , one zoosporic, H. northumbrica , and one aplanosporic, H. polymorphs, , were isolated from samples of manure and horse dung in north-east England. The zoosporic H. northumbrica is morphologically similar to H. dickii but differs in having slightly smaller infection gun cells with a unique internal arrangement of cones in the apical missile chamber. The thallus of the aplanosporic H. polymorpha is similar to H. heteromorpha but produces three different types of aplanospore. The smaller cysts either develop into broad, arcuate gun cells or form curved adhesive cells that have a rounded base. These curved adhesive cells have very different internal ultrastructural organization. The large cysts develop into infection cells that are morphologically similar to the curved adhesive cells, but their internal structure has not yet been observed. 相似文献