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1.
A marine green alga,Chlamydomonas sp. strain MGA161 was cultivated under illumination of red and white lights. The growth rate under red light illumination was almost the same as that in the basic conditions under white light illumination, but red light-grown cells accumulated almost twice as much starch as white light-grown cells. Although there was a slight decrease in carbonic anhydrase activity, red light-illuminated cells had almost 2.3 times the fructose-l,6-diphos-phatase activity of white light-illuminated cells. Red light might stimulate starch accumulation by increasing the amounts of enzymes related to carbon fixation through the phytochrome system. Cells grown under red light degraded 1.6 times as much starch and produced 1.7 times as much hydrogen and 1.6 times as much ethanol compared with cells grown under white light during 12 h of dark anaerobic fermentation.  相似文献   

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A comparison is made amongst the isosteric Systems quinoline, thieno[2,3,-b]pyridine, and thieno[3,2-b]-pyridine which bear the 1-carboethoxy-1-cyanomethyl substituent (R) alpha or gamma to the heterocyclic nitrogen atom. Treatment of thieno[3,2-b]pyridine 4-oxide with ethyl cyanoacetate and acetic anhydride at room temperature (Hamana reaction) gives the alpha R-derivative 6 (27%), formulated as an intramolecular H-bonded structure. Neither 6 nor its quinoline alpha analog reacts with refluxing acetic anhydride, while the quinoline gamma isomer 8 , existing as NH and CH tautomers, yields an N-acetyl derivative 10 (70%) under similar conditions. For each of 6 and 8 one can isolate two crystalline forms which differ considerably in color. Compound 10 and its gamma analog in the thieno[2,3-6]pyridine series (previously obtained directly from a Hamana reaction) serve as acetylating agents for aniline, 1-aminobutane, morpholine, and cholesterol. Correlations and contrasts in the three Systems are presented.  相似文献   

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Applied Biochemistry and Biotechnology - The addition of NH4Cl at concentrations of more than 1 mM completely inhibited nitrogenase-dependent hydrogen evolution using 1 mM succinate as a substrate...  相似文献   

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To rationalize coherence and mechanochemical aspects of proteins acting as molecular machines, a plasmon concept for dealing with protein nonequilibrium dynamics is introduced and tested with respect to thermodynamic consistency. A stochastic optimum-control theory for protein conformational diffusion is developed and the corresponding stochastic Newton's second law derived for optimum-controlled conformational diffusion in proteins. The plasmon concept is shown to be consistent with this theory, in that optical plasmons can pump entropy out of (or into) the protein, decreasing (or increasing) its conformational diffusion and, at the same time, help decrease intra- and intermolecular friction, as well as (potentially) break the symmetry of the latter. Instead, acoustic plasmons may break the spatial symmetry of a protein's "potential of mean force", thus converting it into an effective Brownian ratchet potential by applying quasistatic deformational corrections to the former. These concepts seem to be of rather general applicability and might also be useful when studying, for example, intercalation of cationic dyes into DNA duplexes, positively charged oligopeptide transduction through cell membranes, or even DNA translocation through nanopores.  相似文献   

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The suitability of a Kalman filter for processing slowly varying parameters of a linear calibration graph is described. After calibration, the recursive algorithm predicts the changing parameters in time, which are used for the evaluation of unknown samples. With a preselected precision of the final results as a proper analytical goal, one may decide successively either to do another unknown sample or to calibrate again. The application of the proposed algorithm is demonstrated with a simulated example based on realistic data.  相似文献   

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JPC – Journal of Planar Chromatography – Modern TLC - The lipophilicity of a series of pyrrolyl-acetic acid derivatives, inhibitors of the aldose reductase enzyme, was assessed by...  相似文献   

11.
Force constants and normal coordinates are reported for the spiropentane molecule. These data are based on the recently determined fundamental vibration frequencies of spiropentane-H8.The results have been used to predict the fundamentals of spiropentane-D8, to calculate the centrifugal distortion parameters, in particular the parameter r6, which is non-zero for molecules with a four-fold axis of rotation and to calculate thermodynamic parameters. Good agreement is observed between the calorimetric vapour heat capacity of spiropentane and the value based on our assignments for the fundamental vibrations of spiropentane.The transferability of the cyclopropane force field has been tested and shown to be valid for predicting the deformations of the methylene groups of spiropentane.  相似文献   

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L ‐Asparaginase from Erwinia chrysanthemi (ASPG_ERWCH; UniProtKB accession number P06608 (Erwinase®)) and L ‐asparaginase 2 from Escherichia coli (ASPG2_ECOLI; UniProtKB accession number P00805 (Medac®)), both L ‐asparagine amidohydrolases, are widely used for the treatment of acute lymphoblastic leukemia. A series of serious side effects have been reported and this warrants studies into the protein chemistry of the medical products sold. Mass spectrometry (MS) data on ASPG_ERWCH and ASPG2_ECOLI have not been published so far and herein a gel‐based proteomics study was performed to provide information about sequence and modifications of the commercially available medical products. ASPG_ERWCH and ASPG2_ECOLI were applied onto two‐dimensional gel electrophoresis, spots were in‐gel digested with several proteases and resulting peptides and protein modifications were analysed by nano‐ESI‐LC‐MS/MS. Four spots were observed for ASPG_ERWCH, six spots were observed for ASPG2_ECOLI and the identified proteins showed high sequence coverage without sequence conflicts. Several protein modifications including technical and posttranslational modifications were demonstrated. Protein modifications are known to change physicochemical, immunochemical, biological and pharmacological properties and results from this work may challenge re‐designing of the product including possible removal of the modifications by the manufacturer because it is not known whether they are contributing to the serious adverse effects of the protein drug.  相似文献   

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A method of registering the pure Faradaic current in anodic stripping voltammetry is described. A computer-controlled voltammetric unit is used. The chemical significance or the voltammograms obtained is discussed. Details of the computer algorithm and results from anodic stripping analysis of metal solutions are given. The design of a mercury-plated glassy carbon electrode is discussed.  相似文献   

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Treatment of the readily available (R)-(-)enantiomer of 2-aminobutan-1-ol 1 with sodium hydride followed by benzyl chloride afforded the O-benzyl base (R)-(-)-2. The latter was successfully used for the resolution of racemic α-methylsuccinic and α-bromosuccinic acids, as well as of the racemic α-benzylhemisuccinic esters 8 and 9 resectively.  相似文献   

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The synthesis of 2H-3, 4-dihydro-3-aminomethyl-1, 4-benzoxazines substituted by one phenyl group in the 2, 3 or α-position is reported. The two diastereoisomers of the 2-phenyl-derivative were independently synthesized from ethyl trans-3-phenylglycidate by a stereospecific route. A previous attempt at the synthesis of these same compounds gave rise to an unexpected aliphatic-aromatic ketone rearrangement.  相似文献   

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We introduce PHASE, a highly flexible system for common pharmacophore identification and assessment, 3D QSAR model development, and 3D database creation and searching. The primary workflows and tasks supported by PHASE are described, and details of the underlying scientific methodologies are provided. Using results from previously published investigations, PHASE is compared directly to other ligand-based software for its ability to identify target pharmacophores, rationalize structure-activity data, and predict activities of external compounds.  相似文献   

18.
Incorporation experiments using sodium [2-14C]-, [2-3H]-, (3R)-[5-14C]- and [2-3H, 2-14C]-mevalonates and with mevalonates stereospecifically tritiated at C(2) demonstrate the transformation of mevalonic acid ( 8 ) into verrucarinic acid ( 5 ). Degradation experiments showed that this transformation occurs with a hydrogen 1, 2-shift of the ‘pro-2R’ hydrogen atom of mevalonate to C(3) of verrucarinate. A possible mechanistic pathway is discussed.  相似文献   

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Reaction of glutarimide with pent-4-enylmagnesium bromide, followed by cyclization of intermediate ketoamide, and hydrolysis of the formates 10 and 13 led to the mixture of the hydroxylactams 11 (cis) and 14 (trans) which could be separated via their benzenecarbamates. Reduction of cis-hydroxylactam 11 with LiAlH4 yielded 2-depentyl-7-debutylperhydrohistrionicotoxin ( 6 ), whereas reduction of trans-isomer 14 gave the epimeric alcohol 9 . cis-Hydroxylactam 11 was converted via thiolactam 17 and the methylthio derivative 18 to ketimine 19 which was reduced with NaBH4 yielding a mixture of natural 4 and unnatural 7 , analogues of perhydrohistrionicotoxin ( 2 ). Reduction of 4 with H2 in the presence of Pd/C yielded (±)-7-debutylperhydrohistrionicotoxin ( 5 ).  相似文献   

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