A NOVEL METAL CHELATE AFFINITY ADSORBENT FOR PROTEIN UPTAKE

In this article,a spherical chitosan gel crosslinked by epichlorohydrin was prepared.It was then loaded with copper ions to produce a metal chelate affinity adsorbent for protein.The uptake of bovine serum albumin(BSA)by the affinity adsorbent was investigated.and the adsorption capacity for BSA as high as 40mg/g-wet beads was observed.The adsorption equilibrium data was well correlated by the Langmuir equation.The adsorption was considerably affected by pH.In additio.The amount of BSA adsorbed onto the beads decreased with the increasing of aqueous phase ionic strength,so adsorbed BAS can be desorbed by adjusting pH orionic strength of the solution.     

曙红Y与牛血清蛋白作用的荧光光谱研究及分析应用

在pH 2.53的介质中,曙红Y与牛血清蛋白（BSA）作用形成复合物,最大吸收峰从513nm红移到529nm,曙红Y荧光光谱发生显著变化,最大发射光波长540nm（最大激发光波长308nm）荧光猝灭,其猝灭程度与BSA含量成正比,线性范围0－2.5mg/L ,相关系数0.999,检出限2.8μg/L(3σ）。作者研究了反应条件、干扰物质及进行了样品测试,结果令人满意。     

Influence of Cyclodextrins on the Kinetics of Oxidation of Amino Acids and BSA by Hydrazyl Radicals

The kinetics of oxidation of amino acids (Arg, His, Lys, Phe, Thr and Tyr), a dipeptide (Gly-His), and BSA (bovine serum albumin) by two persistent water soluble free radicals of the hydrazyl type has been studied.The rate decreases in the order Arg>Lys>Tyr>Thr>HisBSAPheGly-His with bothfree radicals. Addition to the reaction mixture of - and -cyclodextrin decreases the oxidation rate, probably due to amino acidencapsulation in the cyclodextrin cavity. -Cyclodextrin protects more efficiently against oxidation than -cyclodextrin.     

Synthesis,crystal structure,and interaction with DNA and BSA of a chromium(III) complex with naph-gly Schiff base and 1,10-phenanthroline

A new chromium(III) complex, [CrCl(naph-gly)phen]?H₂O (naph-gly = Schiff base derived from 2-hydroxy-1-naphthaldehyde and glycine, phen = 1,10-phenanthroline), has been synthesized and characterized by elemental analysis, electrospray ionization mass spectroscopy, FT-IR, and X-ray single-crystal diffraction. The chromium(III) complex belongs to the trigonal crystal system, P3(1) space group with crystallographic data: a = b = 1.97017(16) nm, c = 1.02991(7) nm, α?=?β?=?90°, γ =120°, V = 3.4621(5) nm³, D_c = 1.476 g?cm^?3, Z = 6, F(0 0 0)?=?1578, R₁ = 0.0508, wR₂ = 0.0907. There are two independent molecules in the crystallographic asymmetric unit of the chromium(III) complex. Each Cr^III is six-coordinate to form an octahedral geometry. In the crystal, a 3-D structure is formed through intermolecular hydrogen bonds. The calf thymus DNA (CT-DNA)- and bovine serum albumin (BSA)-binding properties of the complex have been studied by UV absorption, fluorescence, and circular dichroism (CD) spectroscopy. Results indicate that the chromium(III) complex binds to CT-DNA in an intercalative mode, and it can bind to BSA and cause conformational changes of BSA.     

Optimization of Gold Nanoparticle-Based DNA Detection for Microarrays

DNA microarrays are promising tools for fast and highly parallel DNA detection by means of fluorescence or gold nanoparticle labeling. However, substrate modification with silanes (as a prerequisite for capture DNA binding) often leads to inhomogeneous surfaces and/or nonspecific binding of the labeled DNA. We examined both different substrate cleaning and activating protocols and also different blocking strategies for optimizing the procedures, especially those for nanoparticle labeling. Contact angle measurements as well as fluorescence microscopy, atomic force microscopy (AFM), and a flatbed scanner were used to analyze the multiple-step process. Although the examined different cleaning and activating protocols resulted in considerably different contact angles, meaning different substrate wettability, silanization led to similar hydrophobic surfaces which could be revealed as smooth surfaces of about 2–4 nm roughness. The two examined silanes (3-glycidoxypropyltrimethoxysilane (GOPS) and 3-aminopropyltriethoxysilane (APTES)) differed in their DNA binding homogeneity, maximum signal intensities, and sensitivity. Nonspecific gold binding on APTES/PDC surfaces could be blocked by treatment in 3% bovine serum albumin (BSA).     

Study by XPS of the chlorination of proteins aggregated onto tin dioxide during electrochemical production of hypochlorous acid

In solution, hypochlorous acid (HOCl) reacts with organic matter and notably with protein side-chains. In this study, HOCl was produced by an electrochemical way, by oxidation of chloride ions at a transparent tin dioxide electrode in the presence of a protein, the bovine serum albumin (BSA). A thick irregular layer is formed at the electrode when HOCl is produced at the SnO₂ surface. Indeed, SEM analyses show that an important deposit is formed during the anodic polarization of SnO₂ in the presence of chloride ions and proteins. Actually, two phenomena take place on the one hand the chlorination of the proteins due to the reaction of HOCl with some protein side-chains and on the other hand the aggregation of proteins onto the SnO₂ surface. The present X-ray photoelectron spectroscopy study points out the cross-linking of BSA molecules via formation of inter molecular sulfonamide groups. It also shows that the BSA chlorination is due on the one hand to the formation of sulfonyl chloride groups (-SO₂Cl) and on the other hand to formation of chloramine groups (N-Cl). The Cl2p and S2p photo-peak intensities allowed us to quantify the chloramines. It is found that, one BSA entity immobilized onto the SnO₂ surface contains about 50 chloramine groups.     

Effect of Laser-Induced Optical Breakdown on the Structure of Bsa Molecules in Aqueous Solutions: An Optical Study

The influence of laser radiation of a typical surgical laser on the physicochemical properties of the Bovine Serum Albumin (BSA) protein was studied. It was established that the physicochemical characteristics of optical breakdown weakly depend on the concentration of protein molecules. At the same time, the patterns observed for an aqueous solution of BSA irradiated with a laser for different time periods were extremely similar to the classical ones. It was established that after exposure to laser radiation, the optical density of protein solutions increases. At the same time, the intensity of BSA fluorescence due to aromatic amino acid residues decreases insignificantly after exposure to laser radiation. In this case, the position of the excitation and emission maximum does not change, and the shape of the fluorescence spot on 3D maps also does not change significantly. On the Raman spectrum after exposure to laser radiation, a significant decrease in 1570 cm⁻¹ was observed, which indicates the degradation of α-helices and, as a result, partial denaturation of BSA molecules. Partial denaturation did not significantly change the total area of protein molecules, since the refractive index of solutions did not change significantly. However, in BSA solutions, after exposure to laser radiation, the viscosity increased, and the pseudoplasticity of aqueous solutions decreased. In this case, there was no massive damage to the polypeptide chain; on the contrary, when exposed to optical breakdown, intense aggregation was observed, while aggregates with a size of 400 nm or more appeared in the solution. Thus, under the action of optical breakdown induced by laser radiation in a BSA solution, the processes of partial denaturation and aggregation prevail, aromatic amino acid residues are damaged to a lesser extent, and fragmentation of protein molecules is not observed.     

牛血清白蛋白的压电免疫测定及电极的洗脱

在镀银石英晶片上用压电免疫方法测定了０．５～５０ｍｇ／Ｌ范围内的牛血清白蛋白的浓度，得到线性响应；并较全面地研究了压电晶片的回复性使用问题，以０．２ｍｏｌ／Ｌ甘氨酸－盐酸（ｐＨ＝２．０）溶液洗脱时效果较好     

Laccase‐catalyzed polymerization of lignocatechol and affinity on proteins of resulting polymers

For the synthesis of a new biologically functional polymer from a natural resource by an environment‐friendly method, the laccase‐catalyzed polymerization of a lignin‐based macromonomer, lignocatechol, was carried out for the first time in ethanol–phosphate buffer solvent system to give crosslinked polymers in good yields. Lignocatechol was prepared by the phase separation system of lignin and catechol in aqueous sulfuric acid. The copolymerization was also performed with urushiol to afford the corresponding copolymers in high yields. The polymerization mechanism was estimated by the IR and pyrolysis GC‐MS measurements, suggesting that the polymerization proceeded mainly at the catechol ring through a quinone radical intermediate. The thermal properties were measured by the DSC, TG, and TMA analyses, indicating that the polymers had high thermal stabilities because of the crosslinked structures. In addition, it was found that the resulting polymers had the affinity of bovine serum albumin (BSA) and glucoamylase. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 824–832, 2009     

Effect of Polyethylene glycol methyl ether blend Humic acid on poly (vinylidene fluoride-co-hexafluropropylene) PVDF-HFP membranes: pH responsiveness and antifouling behavior with optimization approach

Flat sheet asymmetric membranes were fabricated with homogeneous solution of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) using N-methyl-2-pyrrolidone (NMP) as solvent via phase inversion method. PEGME (Poly ethylene glycol methyl ether) (M_n 5000) blend Humic Acid (HA), of different mole ratio was used as additive. Characterization of the membranes was done by Field emission scanning electron microscope (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, Atomic force microscopy (AFM) and Differential scanning calorimetry (DSC) studies. Liquid-liquid displacement porosimetry (LLDP) study evaluated the morphological parameters, average pore size and pore size distribution. Bovine serum albumin (BSA) (M_W - 68,000 Da) was used to study the antifouling effect and pore blocking mechanism of the membranes. The pure water flux (PWF), solute rejection and flux recovery ratio drastically increases for the PEGME blended HA membranes whereas the water contact angle decreases significantly. The pH responsiveness character of the prepared membranes altered the hydraulic permeability and rejection % at different pH. Finally, optimization of the variables contributing towards the PWF and BSA rejection of the desired membrane was performed using Design expert software 9.0 TRIAL through ANOVA (analysis of variance) using the combination of response surface methodology (RSM) and central composite design (CCD).