UV-induced graft polymerization of acrylic acid(AA) on poly(ether ether ketone)(PEEK) films was carried out to introduce ―COOH for the subsequent immobilization of bovine serum albumin(BSA).BSA was introduced...UV-induced graft polymerization of acrylic acid(AA) on poly(ether ether ketone)(PEEK) films was carried out to introduce ―COOH for the subsequent immobilization of bovine serum albumin(BSA).BSA was introduced on PEEK surface based on the condensation reaction between ―NH 2 and ―COOH.The modified surface(PEEK-BSA) was characterized by energy-disperse spectrometry(EDS),X-ray photoelectron spectroscopy(XPS),water contact angle measurement and UV spectrum analysis.The contact angle was found to decrease from 104° for the virgin PEEK films to 63° for the BSA-immobilized PEEK films,demonstrating a significant improvement of surface hydrophilicity.Moreover,the appearance of nitrogen on PEEK film confirmed by XPS and EDS indicates the immobilization of BSA on PEEK surface.展开更多
The sonocatalytic damage of bovine serum albumin (BSA) was studied in the presence of nanometer titanium dioxide (TiO2) powders by low frequency (80 kHz) ultrasound. The destruction of secondary structure and ch...The sonocatalytic damage of bovine serum albumin (BSA) was studied in the presence of nanometer titanium dioxide (TiO2) powders by low frequency (80 kHz) ultrasound. The destruction of secondary structure and change of α-helical structure of BSA were reflected by ultraviolet (UV) and circular dichroism (CD) spectroscopies.展开更多
The interaction between bovine serum albumin (BSA) and the anionic 1.2-dipalmitoyl-snglycero- 3-(phospho-rac-(1-glycerol)) (sodium salt) (DPPG) phospholipid at different subphase pH values was investigated a...The interaction between bovine serum albumin (BSA) and the anionic 1.2-dipalmitoyl-snglycero- 3-(phospho-rac-(1-glycerol)) (sodium salt) (DPPG) phospholipid at different subphase pH values was investigated at air-water interface through surface pressure measurements and atomic force microscopy (AFM) observation. By analyzing surface pressure-mean molecular area (π-A) isotherms, the limiting molecular area in the closed packing state-the concentration of BSA (Alim-[BSA]) curves, the compressibility coefficient-surface pressure (CS-1-π) curves and the difference value of mean molecular area-the concentration of BSA (ΔA-[BSA]) curves, we obtained that the mean molecular area of DPPG monolayer became much larger when the concentration of BSA in the subphase increased at pH=3 and 5. But the isotherms had no significant change at different amount of BSA at pH=10. In addition, the amount of BSA molecules adsorbed onto the lipid monolayer reached a threshold value when [BSA]〉5×10-8 mol/L for all pHs. From the surface pressure-time (π-t) data, we obtained that desorption and adsorption processes occurred at pH=3, however, there was only desorption process occurring at pH=5 and 10. These results showed that the interaction mechanism between DPPG and BSA molecules was affected by the pH of subphase. BSA molecules were adsorbed onto the DPPG monolayers mainly through the hydrophobic interaction at pH=3 and 5, and the strength of hydrophobic interaction at pH=3 was stronger than the case of pH=5. At pH=10, a weaker hydrophobic interaction and a stronger electrostatic repulsion existed between DPPG and BSA molecules. AFM images revealed that the pH of subphase and [BSA] could affect the morphology features of the monolayers, which was consistent with these curves. The study provides an important experimental basis and theoretical support to understand the interaction between lipid and BSA at the air-water interface.展开更多
Glutamic acid-salicylaldehyde Schiff-base metal complexes are bound into bovine serum albumin (BSA), which afforded BSA binding Schiff-base metal complexes (BSA-SalGluM, M=Cu, Co, Ni, Zn). The BSA binding metal co...Glutamic acid-salicylaldehyde Schiff-base metal complexes are bound into bovine serum albumin (BSA), which afforded BSA binding Schiff-base metal complexes (BSA-SalGluM, M=Cu, Co, Ni, Zn). The BSA binding metal complexes were characterized by UV-vis spectra and Native PAGE. It showed that the protein structures of BSA kept after coordinating amino acid Schiff-bases metal complexes. The effect of the antioxidant activity was investigated. The results indicate that the antioxidant capacity of BSA increased more than 10 times after binding Schiff-base metal complexes.展开更多
Bovine serum albumin (BSA) was labeled with 9,10-anthraquinone and the photochemical fluorimetric reactivity of the covalently conjugated 9,10-anthraquinone was remarkably improved. The mechanism for the enhancement i...Bovine serum albumin (BSA) was labeled with 9,10-anthraquinone and the photochemical fluorimetric reactivity of the covalently conjugated 9,10-anthraquinone was remarkably improved. The mechanism for the enhancement in the photochemical reactivity of conjugated 9,10-anthraquinone with BSA was discussed.展开更多
The quenching interaction of atomoxetine(ATX) with bovine serum albumin(BSA) was studied in vitro under optimal physiological condition(pH=7.4) by multi-spectroscopic techniques. The mechanism of ATX-BSA system was a ...The quenching interaction of atomoxetine(ATX) with bovine serum albumin(BSA) was studied in vitro under optimal physiological condition(pH=7.4) by multi-spectroscopic techniques. The mechanism of ATX-BSA system was a dynamic quenching process and was confirmed by the fluorescence spectra and lifetime measurements. The number of binding sites, binding constants and other binding characteristics were computed. Thermodynamic parameters ΔH^0 and ΔS^0 indicated that intermolecular hydrophobic forces predominantly stabilized the drug-protein system. The average binding distance between BSA and ATX was studied by F?rsters theory. UV-absorption, Fourier transform infrared spectroscopy(FT-IR), circular dichroism(CD), synchronous spectra and three-dimensional(3D) fluorescence spectral results revealed the changes in micro-environment of secondary structure of protein upon the interaction with ATX. Displacement of site probes and the effects of some common metal ions on the binding of ATX with BSA interaction were also studied.展开更多
In vitro interaction of sildenafil citrate (SC) with bovine serum albumin (BSA) was investigated at two excitation wavelengths of BSA (280 nm and 293 nm) at two different temperatures (298 K and 308 K) by fluorescence...In vitro interaction of sildenafil citrate (SC) with bovine serum albumin (BSA) was investigated at two excitation wavelengths of BSA (280 nm and 293 nm) at two different temperatures (298 K and 308 K) by fluorescence emission spectroscopy. The study showed that quenching of BSA fluores-cence by sildenafil citrate was the result of formation BSA-SC complex with probable involvement of both tryptophan and tyrosine residues of BSA. Fluorescence quenching constant was determined from Stern-Volmer equation, and both static quenching and dynamic quenching were showed for BSA by SC at the conditions. Van’t Hoff equation was used to measure the thermodynamic parameters ΔG, ΔH, and ΔS at the temperatures which indicated that the hydrogen bond and the hydrophobic forces played major roles for BSA-SC complexation. The binding number (n) was found to be ≈1 indicating that one mole BSA bound with one mole SC. The binding affinity of SC to BSA was calculated at different temperatures. The binding constant was decreased with increasing temperatures indicating that stability of BSA-SC complex decreased with increasing temperatures.展开更多
In this work, a novel method was constructed to determine the enantiomeric composition of tryptophan (Trp) by bovine serum albumin (BSA) based on the fluorescence spectra of the receptor-ligand mixtures coupled wi...In this work, a novel method was constructed to determine the enantiomeric composition of tryptophan (Trp) by bovine serum albumin (BSA) based on the fluorescence spectra of the receptor-ligand mixtures coupled with partial least squares (PLS-1) analysis. As a result the enantiomeric composition of Trp was accurately determined.展开更多
The interaction of raltitrexed(RTX) with bovine serum albumin(BSA) was investigated by steady state/lifetime fluorescence spectroscopy and circular dichroism(CD) spectroscopy under the simulative physiological c...The interaction of raltitrexed(RTX) with bovine serum albumin(BSA) was investigated by steady state/lifetime fluorescence spectroscopy and circular dichroism(CD) spectroscopy under the simulative physiological conditions.The results of fluorescence titration reveal that RTX could strongly quench the intrinsic fluorescence of BSA via a static quenching procedure.The obtained binding constant K A of RTX with BSA was 478630 and 44259 L/mol at 298 and 310 K,respectively.According to van't Hoff equation,the thermodynamic parameters ΔH,ΔG and ΔS were calculated,indicating that hydrophobic forces were the predominant intermolecular forces in stabilizing the complex.The binding process was a spontaneous process,in which Gibbs free energy change was negative.According to F rster's non-radioactive energy transfer theory,the distance r between donor(BSA) and acceptor(RTX) was 3.82 nm,suggesting that the energy transfer from BSA to RTX occurred with high probability.Displacement experiment and the number of binding sites calculation confirmed that RTX could bind to the site-I of BSA.Furthermore,the effects of pH and some metal ions on the interaction of RTX with BSA were also investigated.The results of synchronous fluorescence and CD spectra show that the RTX-BSA binding induced conformational changes in BSA.展开更多
Protein denaturation is under intensive research, since it leads to neurological disorders of severe consequences. Avoiding denaturation and stabilizing the proteins in their native state is of great importance,especi...Protein denaturation is under intensive research, since it leads to neurological disorders of severe consequences. Avoiding denaturation and stabilizing the proteins in their native state is of great importance,especially when proteins are used as drug molecules or vaccines. It is preferred to add pharmaceutical excipients in protein formulations to avoid denaturation and thereby stabilize them. The present study aimed at using bile salts(BSs), a group of well-known drug delivery systems, for stabilization of proteins.Bovine serum albumin(BSA) was taken as the model protein, whose association with two BSs, namely sodium cholate(Na C) and sodium deoxycholate(Na DC), was studied. Denaturation studies on the preformed BSA-BS systems were carried out under chemical and physical denaturation conditions. Urea was used as the chemical denaturant and BSA-BS systems were subjected to various temperature conditions to understand the thermal(physical) denaturation. With the denaturation conditions prescribed here,the data obtained is informative on the association of BSA-BS systems to be hydrophobic and this effect of hydrophobicity plays an important role in stabilizing the serum albumin in its native state under both chemical and thermal denaturation.展开更多
The porphyrins tailed with acetylsalicylic acid (ASA) and Zn (or Cu) complexes were prepared. Meanwhile, morphological images, such as shape and size of porphyrins-BSA congeries were observed by using atomic force...The porphyrins tailed with acetylsalicylic acid (ASA) and Zn (or Cu) complexes were prepared. Meanwhile, morphological images, such as shape and size of porphyrins-BSA congeries were observed by using atomic force microscopy (AFM). The result showed the interaction of BSA and prepared porphyrins led to obvious change of shape and size of BSA congeries.展开更多
We previously studied the mechanism underlying the adsorption of oral bacteria on the surfaces of dental prosthetic materials such as ceramics and resins in vitro. The aim of the present study was to examine bovine se...We previously studied the mechanism underlying the adsorption of oral bacteria on the surfaces of dental prosthetic materials such as ceramics and resins in vitro. The aim of the present study was to examine bovine serum albumin (BSA) adsorption on crown composite resin surfaces by means of zeta potential. We measured the zeta potentials of resins alone, BSA alone, and resins after BSA adsorption. Eight resins were pulverized into powders (300 - 1000 nm). All experiments were conducted in 10 mM sodium chloride solution (pH 6.5). BSA was dissolved in 10 mM NaCl with a concentration of 2.0 × 10-5 mol/l. An adsorption assay was performed for one hour at 37°C under continuous rotation (6 rpm). The zeta potentials of both resins and BSA were negative, with BSA itself less negative than the resins themselves as an absolute value (p < 0.0001). The zeta potentials of seven resin surfaces after BSA adsorption were significantly less negative than were those of the resins without BSA adsorption (p < 0.0001). Eight resins were divided into two classes based on the size of the surface potential difference between each resin and the BSA. The difference in surface potential between the resins and the BSA were small, leading to the theory that particles with identical charges repulse each other, and the amounts of adsorbed BSA on these resins might be less. On the other, when the differences between the other resins and BSA are large, so that the repulsive force between two nonidentical particles becomes zero and an attractive force might be generated, then more BSA might be adsorbed on those resins. Therefore, the zeta potentials were affected by BSA adsorption and became less negative. These results suggested that electrostatic interactions play an important role in the adsorption of BSA on resin surfaces.展开更多
The interaction between clarithromycin (CAM) and bovine serum albumin (BSA) was investigated using linear-sweep voltammetry in pH 7.4 phosphate buffer solution where CAM caused two irreversible reduction waves P2 and ...The interaction between clarithromycin (CAM) and bovine serum albumin (BSA) was investigated using linear-sweep voltammetry in pH 7.4 phosphate buffer solution where CAM caused two irreversible reduction waves P2 and P3 on mercury electrode. The study showed that the formation constant and formation ratio for the interaction between CAM and BSA were 1.51 × 10(12) and 3:1 for P2, 4.53 × 10(5) and 1:1 for P3, respectively. The ion strength enhanced the hydrophobic interaction between CAM and BSA.展开更多
The interaction of CdSe quantum dots (QDs) with bovine serum albumin (BSA) has been investigated with ultraviolet visible absorption spectroscopy (UVAS). It was found that the absorption intensity of CdSe QDs si...The interaction of CdSe quantum dots (QDs) with bovine serum albumin (BSA) has been investigated with ultraviolet visible absorption spectroscopy (UVAS). It was found that the absorption intensity of CdSe QDs significantly decreased after adding BSA solution, showing that CdSe QDs were bonded to BSA. The binding molar ratio was 1:1 and the binding constant was 9.7 × 10^6 L mol^-1.展开更多
The title compound, methyl 4-(2,4-dichlorophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate(C_(20) H_(21)Cl_2NO_3, 1) was synthesized and the crystal structure was —determined by single-cryst...The title compound, methyl 4-(2,4-dichlorophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate(C_(20) H_(21)Cl_2NO_3, 1) was synthesized and the crystal structure was —determined by single-crystal X-ray diffraction. It crystallizes in tetragonal system, space group P421 c with a = 16.076(3), b = 16.076(3), c = 14.750(2) ?, V = 3811.8(14) ?3, Z = 8, R = 0.0377 and wR = 0.0845. The interactions between compound 1 and bovine serum albumin(BSA) were investigated using fluorescence spectroscopy. The results revealed that compound 1 can effectively quench the intrinsic fluorescence of BSA by static quenching mechanism. The thermodynamic parameters revealed that the action forces between compound 1 and BSA were mainly van der Waals forces and hydrogen bonds. According to F?rster's non-radioactive energy transfer theory, the binding distance between compound 1 and BSA had been determined. Furthermore, the synchronous fluorescence showed that compound 1 has few effects on the microenvironment and conformation of BSA in the binding process.展开更多
Atomic force microscopy (AFM) was used to study the competitive adsorption betweenbovine serum albumin (BSA) and type Ⅰ collagen on hydrophilic and hydrophobic silicon wafers.BSA showed a grain shape and the type Ⅰ ...Atomic force microscopy (AFM) was used to study the competitive adsorption betweenbovine serum albumin (BSA) and type Ⅰ collagen on hydrophilic and hydrophobic silicon wafers.BSA showed a grain shape and the type Ⅰ collagen displayed fibril-like molecules with relativelyhomogeneous height and width, characterized with clear twisting (helical formation). These AFMimages illustrated that quite a lot of type Ⅰ collagen appeared in the adsorption layer on hydrophilicsurface in a competitive adsorption state, but the adsorption of BSA was more preponderant than thatof type Ⅰ collagen on hydrophobic silicon wafer surface. The experiments showed that theinfluence of BSA on type Ⅰ collagen adsorption on hydrophilic surface was less than that onhydrophobic surface.展开更多
Solid lipid nanoparticles loaded with bovine serum albumin(BSA) were prepared by a double emulsion method. As the mass fraction of the model drug BSA increased from 0 to 15%, the particle size gradually increased. T...Solid lipid nanoparticles loaded with bovine serum albumin(BSA) were prepared by a double emulsion method. As the mass fraction of the model drug BSA increased from 0 to 15%, the particle size gradually increased. The physical stability of the nanoparticles was investigated by zeta potential measurement and they were shown to be quite stable. Fluorescence spectroscopy confirmed that the loaded position of BSA was on the interface between the inner aqueous phase and the solid lipid phase. Both Fourier-transform infrared spectroscopy and circular dichroism spectra indicate that BSA in the nanoparticles was not destroyed, but the secondary structure was disrupted slightly.展开更多
This paper reports that at a newly constructed small-angle x-ray scattering station of Beijing Synchrotron Radia- tion Facility, the topological shape of ligand-free bovine serum albumin in solution has been investiga...This paper reports that at a newly constructed small-angle x-ray scattering station of Beijing Synchrotron Radia- tion Facility, the topological shape of ligand-free bovine serum albumin in solution has been investigated. An appropriate scattering curve is obtained and the calculated value of the gyration radius is 31.2~=t=0.25 ~_ (11=0.1 nm) which is co- incident with other ones' results. It finds that the low-resolution structure models obtained by making use of ab initio reconstruction methods are fitting the crystal structure of human serum albumin very well. All of these results perform the potential of the beamline to apply to structural biology studies. The characteristics, the defects, and the improving measures of the station in future are also discussed.展开更多
The irreversible conformational transition of bovine serum albumin (BSA) from α-helix to β-sheet, induced by electric field near the electrode surface, was monitored by circular dichroism (CD) with a long optical pa...The irreversible conformational transition of bovine serum albumin (BSA) from α-helix to β-sheet, induced by electric field near the electrode surface, was monitored by circular dichroism (CD) with a long optical path thin layer cell (LOPTLC).展开更多
[Objective]The aim was to study the interaction characteristic of bovine serum albumin (BSA) and carbofuran. [ Method]With synchronous fluorescence spectrometry adopted, the interaction of carbofuran and BSA in Tris...[Objective]The aim was to study the interaction characteristic of bovine serum albumin (BSA) and carbofuran. [ Method]With synchronous fluorescence spectrometry adopted, the interaction of carbofuran and BSA in Tris-HCI buffer system (pH 7.40) was investigated. The binding constants at different temperatures were calculated and the interaction types between carbofuran and BSA were discussed. [ Result] Under normal physiological conditions, higher quenching effect of carbofuran on BSA was electrostatic interaction. The changes of different drug concentrations and temperature proved a static quenching of carbofuran with BSA. The binding constants (KSV) at 25 ℃, 37 ℃ and 50 ℃ were 1.17 × 10^4, 1.07 × 10^4 and 0. 99 × 10^4 L/mol respectively with ratio of carbofuran and BSA at 1 : 1. [ Conclusion ] The research is of guiding significance for learning transport and metabolism of carbofuran at molecular level.展开更多
基金Supported by the Scientific and Technological Development Programs of Beijing Municipal Education Commission,China(No.KM201010011004)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education,China,the 2011 Merit-based Research Funding for Picked Returned Overseas Scholars,Beijing Municipality(China)the Research Project Approved for Graduate Students of Beijing Technology and Business University,China(No.19000101026)
文摘UV-induced graft polymerization of acrylic acid(AA) on poly(ether ether ketone)(PEEK) films was carried out to introduce ―COOH for the subsequent immobilization of bovine serum albumin(BSA).BSA was introduced on PEEK surface based on the condensation reaction between ―NH 2 and ―COOH.The modified surface(PEEK-BSA) was characterized by energy-disperse spectrometry(EDS),X-ray photoelectron spectroscopy(XPS),water contact angle measurement and UV spectrum analysis.The contact angle was found to decrease from 104° for the virgin PEEK films to 63° for the BSA-immobilized PEEK films,demonstrating a significant improvement of surface hydrophilicity.Moreover,the appearance of nitrogen on PEEK film confirmed by XPS and EDS indicates the immobilization of BSA on PEEK surface.
基金We greatly acknowledge the National Natural Science Foundation of China for financial support.
文摘The sonocatalytic damage of bovine serum albumin (BSA) was studied in the presence of nanometer titanium dioxide (TiO2) powders by low frequency (80 kHz) ultrasound. The destruction of secondary structure and change of α-helical structure of BSA were reflected by ultraviolet (UV) and circular dichroism (CD) spectroscopies.
基金This work was supported by the National Natural Science Foundation of China (No.21402114), the Natural Science Basic Research Plan in Shaanxi Province of China (2016JM2010 and 2014JM1013), the Fundamental Research Funds for the Central Universities (2017CSY004, GK201603026).
文摘The interaction between bovine serum albumin (BSA) and the anionic 1.2-dipalmitoyl-snglycero- 3-(phospho-rac-(1-glycerol)) (sodium salt) (DPPG) phospholipid at different subphase pH values was investigated at air-water interface through surface pressure measurements and atomic force microscopy (AFM) observation. By analyzing surface pressure-mean molecular area (π-A) isotherms, the limiting molecular area in the closed packing state-the concentration of BSA (Alim-[BSA]) curves, the compressibility coefficient-surface pressure (CS-1-π) curves and the difference value of mean molecular area-the concentration of BSA (ΔA-[BSA]) curves, we obtained that the mean molecular area of DPPG monolayer became much larger when the concentration of BSA in the subphase increased at pH=3 and 5. But the isotherms had no significant change at different amount of BSA at pH=10. In addition, the amount of BSA molecules adsorbed onto the lipid monolayer reached a threshold value when [BSA]〉5×10-8 mol/L for all pHs. From the surface pressure-time (π-t) data, we obtained that desorption and adsorption processes occurred at pH=3, however, there was only desorption process occurring at pH=5 and 10. These results showed that the interaction mechanism between DPPG and BSA molecules was affected by the pH of subphase. BSA molecules were adsorbed onto the DPPG monolayers mainly through the hydrophobic interaction at pH=3 and 5, and the strength of hydrophobic interaction at pH=3 was stronger than the case of pH=5. At pH=10, a weaker hydrophobic interaction and a stronger electrostatic repulsion existed between DPPG and BSA molecules. AFM images revealed that the pH of subphase and [BSA] could affect the morphology features of the monolayers, which was consistent with these curves. The study provides an important experimental basis and theoretical support to understand the interaction between lipid and BSA at the air-water interface.
文摘Glutamic acid-salicylaldehyde Schiff-base metal complexes are bound into bovine serum albumin (BSA), which afforded BSA binding Schiff-base metal complexes (BSA-SalGluM, M=Cu, Co, Ni, Zn). The BSA binding metal complexes were characterized by UV-vis spectra and Native PAGE. It showed that the protein structures of BSA kept after coordinating amino acid Schiff-bases metal complexes. The effect of the antioxidant activity was investigated. The results indicate that the antioxidant capacity of BSA increased more than 10 times after binding Schiff-base metal complexes.
文摘Bovine serum albumin (BSA) was labeled with 9,10-anthraquinone and the photochemical fluorimetric reactivity of the covalently conjugated 9,10-anthraquinone was remarkably improved. The mechanism for the enhancement in the photochemical reactivity of conjugated 9,10-anthraquinone with BSA was discussed.
基金Karnatak University, Dharwad, India, for providing UGC-UPE fellowshipUGC, New Delhi for the award of BSR Faculty Fellowship (F No.18-1/2011) to Prof. S.T. Nandibewoor
文摘The quenching interaction of atomoxetine(ATX) with bovine serum albumin(BSA) was studied in vitro under optimal physiological condition(pH=7.4) by multi-spectroscopic techniques. The mechanism of ATX-BSA system was a dynamic quenching process and was confirmed by the fluorescence spectra and lifetime measurements. The number of binding sites, binding constants and other binding characteristics were computed. Thermodynamic parameters ΔH^0 and ΔS^0 indicated that intermolecular hydrophobic forces predominantly stabilized the drug-protein system. The average binding distance between BSA and ATX was studied by F?rsters theory. UV-absorption, Fourier transform infrared spectroscopy(FT-IR), circular dichroism(CD), synchronous spectra and three-dimensional(3D) fluorescence spectral results revealed the changes in micro-environment of secondary structure of protein upon the interaction with ATX. Displacement of site probes and the effects of some common metal ions on the binding of ATX with BSA interaction were also studied.
文摘In vitro interaction of sildenafil citrate (SC) with bovine serum albumin (BSA) was investigated at two excitation wavelengths of BSA (280 nm and 293 nm) at two different temperatures (298 K and 308 K) by fluorescence emission spectroscopy. The study showed that quenching of BSA fluores-cence by sildenafil citrate was the result of formation BSA-SC complex with probable involvement of both tryptophan and tyrosine residues of BSA. Fluorescence quenching constant was determined from Stern-Volmer equation, and both static quenching and dynamic quenching were showed for BSA by SC at the conditions. Van’t Hoff equation was used to measure the thermodynamic parameters ΔG, ΔH, and ΔS at the temperatures which indicated that the hydrogen bond and the hydrophobic forces played major roles for BSA-SC complexation. The binding number (n) was found to be ≈1 indicating that one mole BSA bound with one mole SC. The binding affinity of SC to BSA was calculated at different temperatures. The binding constant was decreased with increasing temperatures indicating that stability of BSA-SC complex decreased with increasing temperatures.
文摘In this work, a novel method was constructed to determine the enantiomeric composition of tryptophan (Trp) by bovine serum albumin (BSA) based on the fluorescence spectra of the receptor-ligand mixtures coupled with partial least squares (PLS-1) analysis. As a result the enantiomeric composition of Trp was accurately determined.
基金Supported by the National Natural Science Foundation of China(No.30973659)
文摘The interaction of raltitrexed(RTX) with bovine serum albumin(BSA) was investigated by steady state/lifetime fluorescence spectroscopy and circular dichroism(CD) spectroscopy under the simulative physiological conditions.The results of fluorescence titration reveal that RTX could strongly quench the intrinsic fluorescence of BSA via a static quenching procedure.The obtained binding constant K A of RTX with BSA was 478630 and 44259 L/mol at 298 and 310 K,respectively.According to van't Hoff equation,the thermodynamic parameters ΔH,ΔG and ΔS were calculated,indicating that hydrophobic forces were the predominant intermolecular forces in stabilizing the complex.The binding process was a spontaneous process,in which Gibbs free energy change was negative.According to F rster's non-radioactive energy transfer theory,the distance r between donor(BSA) and acceptor(RTX) was 3.82 nm,suggesting that the energy transfer from BSA to RTX occurred with high probability.Displacement experiment and the number of binding sites calculation confirmed that RTX could bind to the site-I of BSA.Furthermore,the effects of pH and some metal ions on the interaction of RTX with BSA were also investigated.The results of synchronous fluorescence and CD spectra show that the RTX-BSA binding induced conformational changes in BSA.
基金DSTSERB,India(SB/FT/CS-032/2012),for the financial support
文摘Protein denaturation is under intensive research, since it leads to neurological disorders of severe consequences. Avoiding denaturation and stabilizing the proteins in their native state is of great importance,especially when proteins are used as drug molecules or vaccines. It is preferred to add pharmaceutical excipients in protein formulations to avoid denaturation and thereby stabilize them. The present study aimed at using bile salts(BSs), a group of well-known drug delivery systems, for stabilization of proteins.Bovine serum albumin(BSA) was taken as the model protein, whose association with two BSs, namely sodium cholate(Na C) and sodium deoxycholate(Na DC), was studied. Denaturation studies on the preformed BSA-BS systems were carried out under chemical and physical denaturation conditions. Urea was used as the chemical denaturant and BSA-BS systems were subjected to various temperature conditions to understand the thermal(physical) denaturation. With the denaturation conditions prescribed here,the data obtained is informative on the association of BSA-BS systems to be hydrophobic and this effect of hydrophobicity plays an important role in stabilizing the serum albumin in its native state under both chemical and thermal denaturation.
文摘The porphyrins tailed with acetylsalicylic acid (ASA) and Zn (or Cu) complexes were prepared. Meanwhile, morphological images, such as shape and size of porphyrins-BSA congeries were observed by using atomic force microscopy (AFM). The result showed the interaction of BSA and prepared porphyrins led to obvious change of shape and size of BSA congeries.
文摘We previously studied the mechanism underlying the adsorption of oral bacteria on the surfaces of dental prosthetic materials such as ceramics and resins in vitro. The aim of the present study was to examine bovine serum albumin (BSA) adsorption on crown composite resin surfaces by means of zeta potential. We measured the zeta potentials of resins alone, BSA alone, and resins after BSA adsorption. Eight resins were pulverized into powders (300 - 1000 nm). All experiments were conducted in 10 mM sodium chloride solution (pH 6.5). BSA was dissolved in 10 mM NaCl with a concentration of 2.0 × 10-5 mol/l. An adsorption assay was performed for one hour at 37°C under continuous rotation (6 rpm). The zeta potentials of both resins and BSA were negative, with BSA itself less negative than the resins themselves as an absolute value (p < 0.0001). The zeta potentials of seven resin surfaces after BSA adsorption were significantly less negative than were those of the resins without BSA adsorption (p < 0.0001). Eight resins were divided into two classes based on the size of the surface potential difference between each resin and the BSA. The difference in surface potential between the resins and the BSA were small, leading to the theory that particles with identical charges repulse each other, and the amounts of adsorbed BSA on these resins might be less. On the other, when the differences between the other resins and BSA are large, so that the repulsive force between two nonidentical particles becomes zero and an attractive force might be generated, then more BSA might be adsorbed on those resins. Therefore, the zeta potentials were affected by BSA adsorption and became less negative. These results suggested that electrostatic interactions play an important role in the adsorption of BSA on resin surfaces.
文摘The interaction between clarithromycin (CAM) and bovine serum albumin (BSA) was investigated using linear-sweep voltammetry in pH 7.4 phosphate buffer solution where CAM caused two irreversible reduction waves P2 and P3 on mercury electrode. The study showed that the formation constant and formation ratio for the interaction between CAM and BSA were 1.51 × 10(12) and 3:1 for P2, 4.53 × 10(5) and 1:1 for P3, respectively. The ion strength enhanced the hydrophobic interaction between CAM and BSA.
文摘The interaction of CdSe quantum dots (QDs) with bovine serum albumin (BSA) has been investigated with ultraviolet visible absorption spectroscopy (UVAS). It was found that the absorption intensity of CdSe QDs significantly decreased after adding BSA solution, showing that CdSe QDs were bonded to BSA. The binding molar ratio was 1:1 and the binding constant was 9.7 × 10^6 L mol^-1.
基金supported by the National Natural Science Foundation of China(61741510)the Science and Technology Research Program of Education department of Jiangxi Province(170928)the Natural Science Foundation of Jiangxi Province(20142BAB213017)
文摘The title compound, methyl 4-(2,4-dichlorophenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate(C_(20) H_(21)Cl_2NO_3, 1) was synthesized and the crystal structure was —determined by single-crystal X-ray diffraction. It crystallizes in tetragonal system, space group P421 c with a = 16.076(3), b = 16.076(3), c = 14.750(2) ?, V = 3811.8(14) ?3, Z = 8, R = 0.0377 and wR = 0.0845. The interactions between compound 1 and bovine serum albumin(BSA) were investigated using fluorescence spectroscopy. The results revealed that compound 1 can effectively quench the intrinsic fluorescence of BSA by static quenching mechanism. The thermodynamic parameters revealed that the action forces between compound 1 and BSA were mainly van der Waals forces and hydrogen bonds. According to F?rster's non-radioactive energy transfer theory, the binding distance between compound 1 and BSA had been determined. Furthermore, the synchronous fluorescence showed that compound 1 has few effects on the microenvironment and conformation of BSA in the binding process.
文摘Atomic force microscopy (AFM) was used to study the competitive adsorption betweenbovine serum albumin (BSA) and type Ⅰ collagen on hydrophilic and hydrophobic silicon wafers.BSA showed a grain shape and the type Ⅰ collagen displayed fibril-like molecules with relativelyhomogeneous height and width, characterized with clear twisting (helical formation). These AFMimages illustrated that quite a lot of type Ⅰ collagen appeared in the adsorption layer on hydrophilicsurface in a competitive adsorption state, but the adsorption of BSA was more preponderant than thatof type Ⅰ collagen on hydrophobic silicon wafer surface. The experiments showed that theinfluence of BSA on type Ⅰ collagen adsorption on hydrophilic surface was less than that onhydrophobic surface.
基金Supported by the National Natural Scientific Foundation of China(No.50472069)the Key Scientific Project from the Chinese Education Ministry(No.106100)
文摘Solid lipid nanoparticles loaded with bovine serum albumin(BSA) were prepared by a double emulsion method. As the mass fraction of the model drug BSA increased from 0 to 15%, the particle size gradually increased. The physical stability of the nanoparticles was investigated by zeta potential measurement and they were shown to be quite stable. Fluorescence spectroscopy confirmed that the loaded position of BSA was on the interface between the inner aqueous phase and the solid lipid phase. Both Fourier-transform infrared spectroscopy and circular dichroism spectra indicate that BSA in the nanoparticles was not destroyed, but the secondary structure was disrupted slightly.
基金Project supported by the Chinese Academy of Science Innovation Key Project (Grant No KJCX2-SW-N06)
文摘This paper reports that at a newly constructed small-angle x-ray scattering station of Beijing Synchrotron Radia- tion Facility, the topological shape of ligand-free bovine serum albumin in solution has been investigated. An appropriate scattering curve is obtained and the calculated value of the gyration radius is 31.2~=t=0.25 ~_ (11=0.1 nm) which is co- incident with other ones' results. It finds that the low-resolution structure models obtained by making use of ab initio reconstruction methods are fitting the crystal structure of human serum albumin very well. All of these results perform the potential of the beamline to apply to structural biology studies. The characteristics, the defects, and the improving measures of the station in future are also discussed.
文摘The irreversible conformational transition of bovine serum albumin (BSA) from α-helix to β-sheet, induced by electric field near the electrode surface, was monitored by circular dichroism (CD) with a long optical path thin layer cell (LOPTLC).
文摘[Objective]The aim was to study the interaction characteristic of bovine serum albumin (BSA) and carbofuran. [ Method]With synchronous fluorescence spectrometry adopted, the interaction of carbofuran and BSA in Tris-HCI buffer system (pH 7.40) was investigated. The binding constants at different temperatures were calculated and the interaction types between carbofuran and BSA were discussed. [ Result] Under normal physiological conditions, higher quenching effect of carbofuran on BSA was electrostatic interaction. The changes of different drug concentrations and temperature proved a static quenching of carbofuran with BSA. The binding constants (KSV) at 25 ℃, 37 ℃ and 50 ℃ were 1.17 × 10^4, 1.07 × 10^4 and 0. 99 × 10^4 L/mol respectively with ratio of carbofuran and BSA at 1 : 1. [ Conclusion ] The research is of guiding significance for learning transport and metabolism of carbofuran at molecular level.