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1.
Anna Michnik K. Michalik A. Kluczewska Zofia Drzazga 《Journal of Thermal Analysis and Calorimetry》2006,84(1):113-117
The thermal denaturation process of bovine and human
both fatty acid containing and fatty acid free albumins in aqueous solution
was studied by use of differential scanning calorimetry. Human serum albumins
were found to be more stable than their bovine counterparts. Fatty acid free
albumins were characterized as generally less stable, more susceptible to
aggregation, their unfolding endothermic transition was less cooperative and
with the smaller degree of reversibility. Deconvolution analysis with using
a non-two-state model with two component transitions showed essential differences
in the thermodynamic parameters between all studied albumins, particularly
regarding the high-temperature component transition. 相似文献
2.
A calorimetric study of thermal denaturation of bovine serum albumin in aqueous solutions has shown essential differences
in stability of fatty acid containing and defatted albumin. The first one shows a single endotherm peak in DSC curve near
69°C with enthalpy change about 1000 kJ mol-1. Defated albumin melts in two different temperature ranges: near 56 and 69°C with enthalpy changes about 300 and 200 kJ mol-1 respectively. Deconvolution analysis shows that the single endotherm is well approximated as the sum of three independent
two-state transitions. Two transitions of bimodal DSC curve for defatted albumin are not of a two-state type. This molecule
melts probably as two structurally independent parts.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Anna Michnik Aleksandra Kłos Zofia Drzazga 《Journal of Thermal Analysis and Calorimetry》2004,77(1):269-277
Protein unfolding events were studied by differential scanning calorimetry (DSC) for bovine serum albumin (BSA) aqueous solutions
exposed to radio-frequency radiation. No immediate effect of this radiation on thermal unfolding of BSA was observed. The
differences between irradiated and control samples have appeared during the storage of BSA solution. The irradiated samples
changed faster than non-irradiated. Our results indicated that the age-related changes were stronger for 3.5 and 5 MHz than
for 247 MHz frequency and dependent on energy power of radiation. Deconvolution of DSC traces allowed to study the effect
of radio-frequency radiation on each component transition.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
应用荧光光谱技术,对尿素与牛血清蛋白在30℃水溶液中的结合作用及造成牛血清蛋白变性的过程进行了研究,获取了尿素诱导牛血清蛋白变性时相对荧光强度和峰位的变化规律.用Pace等提出的公式分析了相对荧光强度数据,得到了牛血清蛋白变性时的伸展分数fu随溶液pH值和尿素浓度的变化规律.求出了变性平衡常数Ku,伸展吉布斯自由能△G... 相似文献
5.
Denaturation study of bovine serum albumin induced by guanidine chloride or urea by microcalorimetry
The denaturation of bovine serum albumin (BSA) induced by guanidine chloride or urea at different pH values was studied by
isothermal microcalorimetry measurements at 30°C. The simple bonding model, which was developed by Privalov, was employed
to obtain the apparent bonding constant K, the apparent singular bonding Gibbs bonding energy ΔG and the total Gibbs energy ΔG(a) between the protein and denaturant, from analysis of the calorimetric data. Furthermore, linear extrapolation at the midpoint
of transition was employed to determine the apparent denaturation enthalpy ΔH
d. The results showed that for guanidine chloride, the bonding between BSA and guanidine chloride could proceed more easily
in an alkaline condition, and the apparent denaturation enthalpy ΔH
d of BSA due to guanidine chloride was 350 kJ·mol−1 at pH 6.97 and 7.05, while it was 275 kJ·mol−1 at pH 9.30, which indicated that BSA was more stabilized in a neutral condition. However, for urea, the bonding between BSA
and urea could proceed more easily in an acidic condition, and the apparent denaturation enthalpy ΔHd of BSA due to urea was
295 kJ · mol−1 at pH 6.97, while it was 230 kJ · mol−1 at pH 7.05 and 9.30. The results indicate that the degree of expansion of BSA in the two denaturants is different.
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Translated from Acta Chimica Sinica, 2008, 66(5) (in Chinese) 相似文献
6.
G. Barone S. Capasso P. Del Vecchio C. De Sena D. Fessas C. Giancola G. Graziano P. Tramonti 《Journal of Thermal Analysis and Calorimetry》1995,45(6):1255-1264
In a previous paper, we report a preliminary DSC study on bovine (BSA) and human (HSA) serum albumins. However, at accurate HPLC analysis the commercial proteins show three peaks: Fraction V-I, probably globulins (as declared by the producers), Fraction V-II (about 15–18% of the product) and Fraction V-III that represents pure BSA or HSA. A hypothesis is that the Fraction II is a covalent dimer, or trimer or a mixture of both, generated during the scalf-life of the commercial product. Denaturation enthalpies of the purified Fraction V-III and Fraction V-II of BSA, have been determined calorimetrically, at changing thepH, and the results of both compared with those obtained on the untreated protein. Few calorimetric experiments have been also carried on a BSA monomer derivative with sulphidril group protected. Computer program have been developed for the deconvolution of exo- and endothermic effects and for the analysis of thermal denaturation profiles. 相似文献
7.
Anna Michnik 《Journal of Thermal Analysis and Calorimetry》2007,87(1):91-96
Human serum albumin unfolding in ethanol/water mixtures was studied
by use of differential scanning calorimetry. Ethanol-induced changes in DSC
curves of defatted and non-defatted albumin were markedly different. In the
presence of ethanol, bimodal denaturation transition for fatty acid free albumin
was observed while that for albumin containing endogenous fatty acids was
single and more sharpen than in aqueous solution. Ethanol was found to decrease
the thermal stability of albumin due to the binding to the unfolded state
to a higher degree than to the native state, thus favouring unfolding. The
binding with different affinities has been suggested depending on ethanol
concentration range. 相似文献
8.
Two classes of binding sites, a single high-affinity site with an association constant of 4·8×106 M−1 and two low-affinity sites with association constant of about 0·05×106 M−1 have been observed in the interaction of Naproxen with bovine serum albumin (BSA). Chemical modification of two tryptophan
residues in BSA with 2-hydroxy-5-nitrobenzyl bromide has led to a reduction in the association constant of the high-affinity
site by 89% and its number of binding sites by 66% suggesting the involvement of tryptophan residues in the high-affinity
site. In contrast, the two low-affinity sites were not affected by the modification. Binding of Naproxen to the low-affinity
sites of BSA induces microdisorganisation of the albumin structure leading to conformational changes as evident from fluorescence
measurements with 1-anilino-8-naphthalenesulphonic acid as the probe. 相似文献
9.
H. N. Kalpana B. C. Channu Chhabil Dass P. J. Houghton K. N. Thimmaiah 《Journal of Chemical Sciences》2000,112(1):51-61
The interaction of 10-(3′-N-morpholinopropyl)phenoxazine [MPP], 10-(4′-N-morpholinobutyl)phenoxazine [MBP], 10-(3′-N-morpholinopropyl)-2-chlorophenoxazine
[MPCP], 10-(3′-N-piperidinopropyl)-2-chlorophenoxazine [PPCP] or 10-(3′-N-morpholinopropyl)-2-trifluoromethylphenoxazine [MPTP]
with bovine serum albumin (BSA) has been studied by gel filtration and equilibrium dialysis methods. The binding of these
modulators, based on dialysis experiments, has been characterized using the following parameters: percentage of bound drug
(Β), the association constant (K
1), the apparent binding constant (k) and the free energy change (δF‡). The binding of phenoxazine derivatives to serum transporter protein, BSA, is correlated
with their octanol-water partition coefficient, log10
P. In addition, effect of the displacing activities of hydroxyzine and acetylsalicylic acid on the binding of phenoxazine derivatives
to albumin has been studied. Results of the displacement experiments show that phenoxazine benzene rings and tertiary amines
attached to the side chain of the phenoxazine moiety are bound to a hydrophobic area on the albumin molecule. 相似文献
10.
Campbell W. Robinson Marc H. Siegel Agn s Condemine Conan Fee Thomas Z. Fahidy Bernard R. Glick 《Journal of membrane science》1993,80(1):209-220
A conventional crossflow ultrafiltration (CUF) apparatus was modified by the inclusion of electrodes which permitted a pulsed electric field to be produced across the ultrafiltration membrane (PEF-UF process). Using this apparatus, a discontinuous electrophoretic velocity was imposed upon the proteins being concentrated, opposing their convective movement toward the CUF membrane. This resulted in a lower concentration of rejected solute protein in the fluid boundary layer adjacent to the high-pressure side of the membrane and, hence, in a lower solute-related filtration resistance than in the case of conventional ultrafiltration (zero electric field). Studies of the PEF-UF process with bovine serum albumin (BSA) in the range of 0.5–5% w/v demonstrated a 25–40% decrease in the solute-related resistance to the permeate flux compared to the case of a zero electric field. Accordingly, higher permeate fluxes and, therefore, higher rates of concentration of the protein solution were obtained than for conventional crossflow ultrafiltration. When the electric field was reimposed following a period of operation under conventional CUF conditions, the permeate flux could be restored to nearly the same higher value observed initially for the PEF-UF process. 相似文献
11.
采用荧光光谱法和热力学方法研究了3-乙基苯并噻唑螺萘并噁嗪(EBSN)与牛血清白蛋白(BSA)的相互作用.结果表明,在pH为7.46的Tris-HCl及0.01mol·L-1的NaCl介质中,EBSN能强烈猝灭BSA的荧光,猝灭机理为形成复合物的静态猝灭.在298、306和313K时,两者的表观结合常数Kb分别为1.762 0×104,3.396 3×104和6.123 5×104 L·mol-1.与此同时,EBSN与BSA的结合反应是自发的,作用力主要为疏水作用力;BSA和EBSN的工作曲线分别为F0-F=2.439c-8.322和(F0-F)/F=0.061 89c+0.556 6,对BSA和EBSN的检出限分别为0.015mg·L-1和7.61×10-7 mol·L-1. 相似文献
12.
甲苯胺蓝与牛血清白蛋白作用的光谱特性研究 总被引:1,自引:0,他引:1
应用荧光光谱法研究了甲苯胺蓝(TB)与牛血清白蛋白(BSA)相互作用的光谱特性.测定了TB与BSA在20℃,30℃和40℃3个温度下的结合常数KA分别为8.94×103,1.75×104,1.74×104L/mol,结合位点数n分别为0.66,0.71和0.93.实验表明:TB与BSA的荧光猝灭主要为静态猝灭;利用Gibbs-Helmholtz方程计算得到热力学参数ΔH为49.416kJ,ΔS为244.876J.mol-1.K-1,探讨了它们的相互作用机理,结果表明TB主要以氢键作用力与BSA相互作用;应用同步荧光技术研究了TB对BSA构象的影响. 相似文献
13.
固定化牛血清白蛋白吸附材料的制备及其对胆红素的吸附性能 总被引:1,自引:0,他引:1
降低高胆红素血症和重症肝炎患者血液中异常升高的胆红素浓度是血浆交换和血液灌流等疗法的目标之一。本文通过共价键合的方法将牛血清白蛋白(BSA)固定在甲基丙烯酸缩水甘油酯共聚三羟甲基丙烷三甲基丙烯酸酯[poly(GMA-co-TMPTMA)]大孔树脂微球上,制备得到对胆红素具良好吸附性能的固定化BSA吸附材料(BIA),吸附容量达48.7mg/g。由于血清白蛋白对胆红素的强烈相互作用,胆红素溶液中游离BSA的存在会显著降低BIA对胆红素的吸附量。BIA对胆红素的吸附量随吸附温度升高而增加。BIA在-80℃下储存31d后性能仍然稳定,对胆红素的吸附量几乎不变。上述结果表明所制备的BIA为以特异性吸附胆红素为目的的血液净化材料提供了新的选择。 相似文献
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18.
The effect of ethanol on human serum albumin stability in aqueous solution
was studied by use of differential scanning calorimetry. A deconvolution of
DSC traces in 2-state model with ΔC
p=0
and ΔC
p≠0
was performed and analysed to obtain information on the interaction of ethanol
with different parts of albumin molecule both fatty acid containing and fatty
acid free. The differences in ethanol binding affinity for both kinds of albumin
were found. At very low concentrations ethanol was observed to be a stabilizer
of the folded state of albumin contrary to the higher concentration where
its binding to the unfolded protein predominates. 相似文献
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20.
N. Watanabe T. Shirakawa M. Iwahashi K. Ohbu T. Seimiya 《Colloid and polymer science》1986,264(10):903-908
The adsorption of bovine serum albumin (BSA) onto a cationic monolayer (N,N-dimethyl-N,N-dialkylammonium chloride) spread at the air/water interface was studied by ellipsometry. Both thicknesses and refractive indices of the BSA layer adsorbed at the monolayer/solution interface are estimated from the observed change in phase difference and the ratio of reflection coefficients. The amount of adsorption of BSA resembles a Langmuir type isotherm. The adsorption changes with pH asymmetrically with respect to the pH of maximum adsorption, which was calculated to be 5.06 ± 0.47 mg/m2. The amount of maximum adsorption implies that the BSA molecule adsorbs to the surface in a mode intermediate between side-on and end-on. 相似文献