Prediction of affinities of peptides for calmodulin

A simple method has been developed to predict the calmodulin-binding domains of peptides and the affinities of the peptides for calmodulin based on a model for the calmodulin-binding domains of peptides proposed in a previous paper and the literature data of calmodulin-binding peptides. The effects of hydrophobitities, α-helix-forming tendencies, and basicities of peptides on their affinities for calmodulin were studied. Model peptides were designed to examine the calmodulin-binding domain model and the prediction method. The determined dissociation constants of the complexes formed from the model peptides and calmodulin are in good agreement with the predicted results.     

Directing Role of Cage Structure for Crystallization of Zeolites

The directing mechanisms of liquid directing agents of zeolite Y and zeolite L were studied by means of light transmission, ultracentrifugation, NMR, XRD and “cross-exchange” experiments. It was discovered that not only microcfystals of zeolites, but also cage structures of zeolites play the directing role for crystallization of zeolites.     

Liposome Immunoassay for Determination of Phenytoin

Inthispaper,arapid,sensitive,andsimpleliposomeimmunoassay(LIA)lbrdetectingphenytoinhasbeenestablished.Phenytoinisuscdtocurecpilepsy,butinclinicalpractice,theefficientconcentrationofphenytoininpatient'sseraisverynarrow,about1O~2Opg/ml.Iftheconcentrationofphenytoininserumislessthantheefficientconcentration,thereisnoeffectofmedicine.Butiftheconcentrationrangewerc2O~4Ollg/ml,themedicinecouldbringsideeffect.Ifthcconcentrationbecomesgreater,thenitcancausepoisoning.Becausetherearemanyfactorswhich…     

Effect of surfactant structure on catalysis of microemulsion for photoisomerization of trans-stilbene

In this study,the photoisomerization of trans-sfilbene was carried out in water in oil (W/O) microemulsions by using sodium dodecyl sulfate (SDS),dodecyl trimethyl ammonium bromide (DTAB) and cetyl trimethyl ammonium bromide (CTAB) as surfactant,respectively.The catalytic effect of microemulsion on this reaction is closely related to the structure of surfactant.When there is no photosensitizer 9,10-dicyanoanthracene (DCA),the surfactant with shorter hydrophobic chain is preferred,while in the presence of DCA,the surfactant with anionic polar group is preferred.     

Computer Aided Study of Mechanism of Immunoadsorbent for Myasthenia Gravis

Myasthenia Gravis (MG) is an organ specific autoimmune disease mediated by autoantibodies (AChR Ab) against the acetylcholine receptor (AChR). Literature reported that the AChR Ab can be removed by absorbent linked with tryotophan.It was studied in detail in our lab. With the aid of computer, we docked some ligandsinto AChR Ab, and the results fromscores of docking under different generations showed that therewas no specific binding between tryptophan and scFv fragment just as the binding between antigen-antibody. The interaction between Trp and immunoglobulin was a broad-spectntm binding.     

Fabrication of column chip made of PMMA for μFIA

We proposed a low cost fabrication procedure of a poly(methylmethacrylate) (PMMA) column chip. 3D microchannel structure consisting of four columns in a chip for a mother die was fabricated using dry film photoresist and photolithography technique. Electroforming was applied to the mother die in order to obtain a Ni mold, then, the pattern was transferred to PMMA by hot press. The column had a dam structure to keep enzyme-immobilized microbeads with volume of 640 nL. The column chip was applied for a micro flow injection analysis (μFIA) system. For a demonstration, we measured lactose using two columns in series. One column was set on upper stream and filled with chitosan microbeads immobilized with β-galactosidase, the other was on downstream and filled with the beads immobilized with glucose oxidase. The lactose detection was accomplished less than 90s after the sample injection. The biosensing system also showed a high performance for lactose detection in wide range of 1 μM to 1mM. These results show that the column chip and our microfluidic biosensing system have the potential to assist minuaturization with small sample volume and short determination time for a sequential analysis.     

EUROSOILS – A set of CRMs for comparability of soil-measurements

An overview is given on the development, properties, and application of the European reference soil set – the EUROSOILS. The introduction of this new type of reference material has, for the first time, enabled comparison of data related to the interaction of chemical substances with the soil, and thus, improvement of soil quality. Because of their unforeseen success, a second generation of EUROSOILS had been produced and the range of application extended to other types of measurement related to the soil matrix – soil pH, carbon and nitrogen content, particle-size distribution and cation-exchange capacity. Other fields of application include analytical method development or testing of soil decontamination techniques. On the basis of the success of the EUROSOIL concept and the need for a common basis for comparison of soil-related data in Europe and beyond, the European Commission’s Institute for Reference Materials and Measurements decided to certify several properties of the second EUROSOIL-generation, thus establishing a common QA/ QC system for soil-related data. The main features of the EUROSOILS, their origin, the necessary field and laboratory work, and some interesting background information about the project are presented in this paper.     

Plasma Treatment of Ni Catalyst for Partial Oxidation of Methane

The 10%Ni/Al2O3 catalyst for partial oxidation of methane was treated by DBD (dielectric barrier discharge) plasma in a continuous system under atmospheric pressure and room temperature by flowing He. It was found that 10%Ni/Al2O3 catalyst treated by plasma presents a higher catalytic activity and an enhanced stability than the catalysts prepared without plasma treatment. The methane conversion over the catalyst treated by plasma is 3%-5% higher than the catalysts untreated by plasma. Moreover,the enhanced dispersion of the catalyst can be achieved by plasma treatment, which can improve the interaction between active species and supports, catalytic activity and the resistance to carbon deposition.     

Study of a toxin–alkaline phosphatase conjugate for the development of an immunosensor for tetrodotoxin determination

This paper describes a direct competitive immunoenzymatic spectrophotometric assay (ELISA) for tetrodotoxin (TTX) determination and the adaptation of this method for use in an electrochemical assay format. The novelty of this work involves the use of the antigen labelled with alkaline phosphatase (AP); this conjugate was prepared in our laboratory as there is no commercially available conjugate of any kind for TTX. The new conjugate was characterized in terms of its affinity for the specific antibody as well as the residual concentration and the residual activity of the enzyme (AP) incorporated as label. The proposed method based on the new conjugate showed satisfactory results for TTX determination: for the spectrophotometric method the dynamic range was 4–15 ng mL⁻¹ with a limit of detection (LOD) of 2 ng mL⁻¹ (R=0.9247), whereas for the electrochemical protocol the dynamic range was 2–50 ng mL⁻¹ and the LOD was1 ng mL⁻¹.     

Synthesis of Bicyclooctane Derivatives for Kinetic Resolution

Theracemicdiacetaterac-l[l]hasprovedtobeaversatilestartingmaterialforthesgnthesisofracemicprostaglandins,suchasll-deoxyPG.,1l-deoxyPGfy,PGA:,PGE,,andPGF.l:1.Bothenantiomerslandent-lcanbetransformedbyenantioc0nvergentroutCsintoenantiomericallypureprostaglandinswiththenatualconfigurationt'].Therefore,thekineticresolutionofitSprecursorrac-2(Schemel)evoked0urinterestinthisfield.CycliccompoundsofthetyPe3shouldbeidealsubstratesforkineticres0luti0noftheendo,endo,bicyclo[3.3.0]octal-2,6-diol2ri…     

Chinese Journal of Chemistry Instructions for Authors

Chinese Journal of Chemistry is an international jour-nal published in English by the Chinese Chemical Soci-ety with its editorial office hosted by Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences. Chinese Journal of Chemistry publishes original re-search work in all fields of chemistry, i.e. physical chemistry, inorganic chemistry, organic chemistry and analytic chemistry, etc., in the forms of Accounts, Arti-cles, Notes and Communications. Each issue contains Grap…     

A New Route for Synthesis of Entecavir

2-Amino-1,9-dihydro-9-[(1S,3R,4S)-4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopen tyl]-6H-purin-6-one (entecavir, Scheme 1) is a novel carbocyclic 2-deoxyguanosine analog drug which has potent and selective anti hepatitis B virus (HBV) activity1-3. Entecavir is also effective against lamivudine-resistant YMDD mutants4. The US Food and Drug Administration (FDA) approved entecavir as a new preferred drug for the treatment of HBV after lamivudine in March, 2005. Scheme 1 The structure o…     

Synthesis of a Photolabeling Probe for the Study of Antiviral Mechanism of Ribavirin

Ribavirin has been used in urgency to treat SARS patients recently. In order to study its antiviral mechanism by photolabeling approach, we have synthesized and characterized 5-azido-1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxiamide 1 as a photolabeling probe of ribavirin. The azidotriazole nucleoside showed rapid and clean photochemical reaction, suggesting that 1 is a promising probe to study the antiviral mechanism ofribarivin by photolabeling.     

Lanthanide Complexes for Oligomerization of Phenyl Isocyanate

IntroductionThestudyonthereactivitiesoflanthanidecomplexesto wardisocyanateshasattractedmuchattention .Ithasbeenre portedthatlanthanidealkoxides,1anddivalentdiaza pentadi enyllanthanidecomplexes2 canbeusedasthesinglecompo nentinitiatorsforisocyanatespolymerization .Recentlyourre searchgrouphasalsofoundthatlanthanoceneamide ,3diva lentaryloxideofsamarium4 ,5anddivalentsamarocene6 areallactivefortheoligomerizationofphenylisocyanate,andtheactivespeciesforthesethreesystemswereallsuccessfullyisolat…     

Chinese Journal of Chemistry Instructions for Authors

Chinese Journal of Chemistry is an intemational jour-nal published in English by the Chinese Chemical Soci-ety with its editorial office hosted by Shanghai Instituteof Organic Chemistry, Chinese Academy of Sciences.     

A New Hapten for Immunoassay of Aldicarb

Aldicarb, 2-methyl-2-(methylthio)propionaldehyde O-(methylcarbamoyl)oxime, is a systemic N-methylcarbamate insecticide and has been used on a variety of crops. It is moderately water soluble and considered as one of the most acutely toxic pesiticides. Ald…     

Novel Bone-targeted Agents for Treatment of Osteoporosis

The novel bone-targeted agents were designed and synthesized by the combination of raloxifene and bisphosphonates. The anti-osteoporosis effect was evaluated by bone mineral density (BMD) obtained from OVX mice in vivo. The results indicated that the compound 8, 9 not only prevented ovariectomy induced loss of bone but also enhanced BMD to 0.87% and 19.67% compared to Sham, respectively.     

An Efficient Way for Glycosylation of Spirostanol

Using thioglycosides as donors, trimethylsilyl trifluoromethanesulfonate (TMSOTf) and N-iodosuccinimide(NIS) as promoter, a modified procedure for the glycosylation of spirostanol was developed. A series of saponins were synthesized in mild condition with excellent yields.     

Investigation of the mechanisms of the action of chemical modifiers for electrothermal atomic absorption spectrometry: what for and how?

Modern trends in the research of the action of chemical modifiers for electrothermal atomic absorption spectrometry (ETAAS) are discussed critically. The most prolific approach is that of investigation of processes occurring during the drying and pyrolysis stages with wide application of data from different fields of chemistry and physics.