Human proinsulin. C-peptide radioimmunoassay method. 125I labeling of human proinsulin. C-petide

125I-labelled human-C-peptide was prepared by chloramin T method, enzymic method and active ester method, respectively. Using respective 125I-labelled human-C-peptides in human proinsulin-C-peptide RIA, we compared the binding (Bo/T%) to antibody, displacement by standard human-C-peptide, the recovery test and stability. The usable 125I-labelled antigen for human proinsulin-C-peptide RIA could be prepared by chloramin T method and enzymic method wich labelled 125I to tyrosyl human proinsulin connecting peptide, and active ester method which conjugates 125I-labelled active ester to human proinsulin connecting peptide. The differences among those 125I-labelled antigens was not observed in displacement (B/Bo%) by standard human-C-peptide and the recovery test. In the case of constant preparation of 125I-labelled antigen for RIA, the enzymic method was the best from the viewpoint the reaction ratio is stable and stability of Bo/T% is good.     

Examination of intermediates in globular protein unfolding by the tritium labeling method

Unfolding of polypeptide chain of ribonuclease A in urea and guanidinium chloride (GuCl) solutions under equilibrium conditions involves formation of intermediates whose properties (compactness and preservation of the most of the native hydrophobic core, secondary structures, and native-like folding of the polypeptide chain) correspond to the basic characteristics of the “molten globule” state. Intermediates are “damp” molten globules (with water molecules inside the globule). The examinations performed revealed pronounced distinctions in the properties of the intermediates, above all, in their compactness degrees.     

On the formation of125IO3 − ions in the Chloramine-T labeling mixture

The formation of¹²⁵IO₃ ^– ions in the course of labeling proteins with¹²⁵I by the use of the Chloramine-T method has been investigated. It was demonstrated that one of the components of the labeling reaction mixture is¹²⁵IO₃ ^–. The identification of radio-iodate ions was performed by the use of paper electrophoresis.     

Double fluorescent labeling method used for a study on liposomes

Carboxyfluorescein (CF) and Calcein (CAL) have almost the same fluorescent spectrum. However, only CAL forms a nonfluorescent chelate with the Co2+ ion. It was proven that this phenomenon can be used for the fractional determination of CF and CAL. And this fractional determination method was available for a study on liposomes.     

The determination of thickness and surface mass density of mesothick immunoprecipitate layers by null ellipsometry and protein 125iodine labeling

The aim of the present study was to ellipsometrically determine the thickness and surface mass density in air for up to 110-nm-thick organic layers made of alternatingly deposited layers of HSA and polyclonal anti-HSA on hydrophobic silicon. The ellipsometrically determined thickness was compared to that obtained by AFM and the deposited surface mass density calibrated with (125)I-labeled proteins. The results indicate a good agreement in protein layer thickness between AFM and ellipsometry when the protein film refractive index N(film)=1.5-0i, although then the calculated surface mass density from the ellipsometry data became grossly overestimated by the Cuypers one-component formula. A good agreement in the surface mass density was obtained when the M/A ratio in this formula was lowered from 4.14 to 2.35. This approach indicates a convenient means of determining the refractive indices and surface mass densities of mesothick organic layers proteins on solid supports.     

Research on the implementing conditions of inverse emulsion-breath figure method

The relationships between three steps of the inverse emulsion-breath figure (Ie-BF) method, including emulsion preparation, film casting and hydrophilic component loading, are explored by adjusting the experimental factors of the three implementing processes. For emulsion preparation step, the influence of the ultrasonification, the concentration of emulsifier and the addition of polymer on the size of the emulsion droplets are investigated. For film casting step, the influence of environmental humidity and several factors concerning the emulsion preparation on the porous structure of the resultant films are studied. It has been proved that high humidity is a necessity for obtaining surface pores, and multi-layered pores with disordered distribution can be formed in the bulk layer of the film when high water/oil ratio is used in making the emulsion. Bovine serum albumin is loaded into the emulsion water droplets, and by implementing the Ie-BF method under the condition of water/oil ratio being as low as 0.02 vol%, selective protein enrichment within the interior of the top-layer pores is still realized. It reflects the characteristics of “high efficiency, targeted assembly” in the step of hydrophilic component loading.     

A novel version of the method of radiofrequency labeling in chemical reactions

A novel version of the radiofrequency labeling method is described, which possesses essential advantages over the recently proposed method of “saturation transfer”. The conditions necessary, for realization of this method are discussed. The use of the method is exemplified by an investigation of a reaction mechanism.     

Facile and efficient postsynthetic tritium labeling method catalyzed by Pd/C in HTO

[reaction: see text] We have developed a facile and efficient tritium labeling method using a Pd/C-HTO-H2 system. This method can provide multitritium-labeled compounds in highly diluted HTO under T2 gas-free conditions, and is environmentally benign since purification by silica gel column chromatography is not necessary, which causes a large quantity of radioactive waste such as silica gel and eluent.     

Simple method for the introduction of iodo-label on (3-trifluoromethyl) phenyldiazirine for photoaffinity labeling

A simple and mild method was developed for the introduction of iodo-label on (3-trifluoromethyl) phenyldiazirine (TPD) aromatic ring in the presence of three membered diazirine ring. An iodination protocol, I₂-BTI in CH₃CN, was found to be effective even though affinity ligands are pre-installed.     

Study of antimony trifluoride by the NQR method

Conclusions We have studied the temperature dependence of the spectral parameters of¹²³Sb NQR for SbF₃. In the 190–215 K interval in SbF₃, we observe a phase transition leading to the appearance of a piezoelectric phase. We have established the temperatures of anomalous behavior of the asymmetry parameter of the electric gield gradient and the region in which a weak magnetic field appears at the antimony nuclei in SbF₃.Translated from Izvestiya Akademii Nauk SSSR, No. 9, pp, 1956–1959, September, 1987.     

Study of π-adsorption by the electroreflection method

The electroreflection spectra for lead and indium electrodes in polarized light have been obtained in a solution containing aniline, benzene and 5-bromo-2-acetylthiophene. In the presence of the above-mentioned additions a new minimum appears at 2.5-2.8 eV in the spectra obtained in p-polarized light. It corresponds to the charge-transfer band in the absorption spectra for adsorbate/electrode complexes. The electrode potential has no influence on the position of this minimum.     

Improved iodine-125 removal in anionic form of iodate by column method using laterite soil

Soil column experiments have been conducted to treat liquid wastes from hospitals containing¹²⁵I. Three sorbent samples of laterite clay materials with different contents of iron oxides (goethite, -FeOOH) and hydroxides were used to sorb anionic iodate. Post-treatment on effluent wastes with sodium hypochlorite (redox reagent) oxidized the iodide to the desirable iodate ion. Effluent pH after treatment ranges between 4.8 to 5.8, which does not vary much from the initial effluent pH of 4.5 before treatment. Results show that 90 to 97% sorption of iodine radionuclides with a decontamination factor ranges between 10–32 was obtained after the first two hours of experiments. Concentration has decreased from the initial 10 Bq/ml to concentration ranges of 0.3 to 0.9 Bq/ml. Batch experiments conducted using different sorbent masses of soils, show that there was a drop in sorption as the mass of soils fell below approximately 0 to 0.25 g. The sorption remains constant with the soil mass above 0.25 g. Another batch experiment using a different concentration shows that the adsorption capacity of the laterite soil was 1.1 Ci/g. The adsorption is about 96% with a distribution coefficient of 1170.     

A combinatorial selective labeling method for the assignment of backbone amide NMR resonances

A combinatorial selective labeling (CSL) method is presented for the assignment of backbone amide NMR resonances, which has a particular application in the identification of protein-ligand interaction sites. The method builds on the dual amino acid selective labeling technique. In the CSL method a number of different samples are produced, each with a different pattern of labeled amino acids. By analyzing peak intensities in HSQC and 2D HNCO spectra of these samples, a large number of combinations of amino acid pairs can be simultaneously assigned. We demonstrate the method on the 27 kDa protein GFP. The samples can be produced rapidly and cost-effectively in a commercially available in vitro translation system. The method greatly simplifies the process of backbone assignment and would be very straightforward to automate.     

用于放射性卤代药物合成的高速无载体固相标记法

本文研究了一种适合于卤素标记化合物的高分子氧化剂的合成及其性能, 研究了适合于某些卤代放射性药物合成的高速、无载体产物的固相标记法和固相反应。 用于肿瘤探针的药物带电诺丹明和肾功能显像剂胆固醇在固定化后, 将这两种药物进行固相法碘标记并对产物进行了鉴定, 得到了放射化学纯度大于95%, 放射性回收率高于96%的标记化合物, 实现了5分钟内完成放射性标记药物无需分离就可得到极高放化纯产物的高速标记法。本文还对其它能生成有机汞化合物的固相标记法进行了讨论。     

An automated method for the analysis of stable isotope labeling data in proteomics

An algorithm is presented for the generation of a reliable peptide component peak table from liquid chromatography-mass spectrometry (LC-MS) and subsequent quantitative analysis of stable isotope coded peptide samples. The method uses chemical noise filtering, charge state fitting, and deisotoping toward improved analysis of complex peptide samples. Overlapping peptide signals in mass spectra were deconvoluted by correlation with modeled peptide isotopic peak profiles. Isotopic peak profiles for peptides were generated in silico from a protein database producing reference model distributions. Doublets of heavy and light labeled peak clusters were identified and compared to provide differential quantification of pairs of stable isotope coded peptides. Algorithms were evaluated using peptides from digests of a single protein and a seven-protein mixture that had been differentially coded with stable isotope labeling agents and mixed in known ratios. The experimental results correlated well with known mixing ratios.     

电解芬顿法处理工业废水

高级氧化技术(AdvancedOxidationProcesses　AOP)是以产生羟基自由基(·OH)为标志。水处理高级氧化技术就是通过化学或物理化学的方法将水中的污染物直接氧化成无机物,或将其转化成为低毒的易生物降解的中间产物,其本质是利用羟基自由基氧化降解水相中的各种污染物的化学反应,是一种有效降解废水中有机污染物的方法。电解芬顿法是利用电解的方法产生Fe2+和H2O2,新生的Fe2+和H2O2立即作用产生·OH。用金属铁作阳极电解溶出Fe2+,或用三维电极,利用阴阳极的协同效应电解产生Fe2+或H2O2[1 4]。与其它AOP法相比,这种方法具有处理成…