Investigation of bovine serum albumin denaturation using ultrasonic spectroscopy
Investigation of bovine serum albumin denaturation using ultrasonic spectroscopy
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超声光谱研究牛血清白蛋白变性
DOI：
10.1016/j.foodhyd.2010.11.011
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发表时间：
2011
影响因子：
10.7
通讯作者：
V. Pinfield
中科院分区：
文献类型：
--
作者：
M. Povey;Jonathan D. Moore;J. Braybrook;Howard Simons;Ron Belchamber;Meera Raganathan;V. Pinfield
超声波光谱法的能力，在相对较高的浓度和食品中发现的条件下，蛋白质变性，检查。在pH 7.0下，测量牛血清白蛋白单体的纵向声速与浓度和频率（20-160 MHz）的关系，得到25 °C下分子压缩系数的频率无关值κ′ = 2.05 × 10− 10 Pa − 1，对应于BSA分子的声速为1920 m s−1。在160 MHz时，BSA分子中的纵向声衰减为1.5200 Np m−1，比水中高10倍。在测量的最高体积分数为0.03（或3% v/v）时，溶液相对于水的过量衰减接近90 Np m− 1。在中性pH和25 °C下，获得了加热至40 mg/mL的牛血清白蛋白（BSA）溶液随时间的浓度依赖性超声速度（20-160 MHz）和衰减（2-120 MHz）光谱。采用声散射模型，将溶质分子视为超声的散射体，确定溶质分子的声速、压缩性和衰减特性。温和的热处理导致分子组织成二聚体和三聚体，而声速没有变化;这意味着二级结构几乎没有变化。衰减光谱的变化与通过DLS和SEC测量确定的估计分子量相关。在寡聚化过程中，BSA分子继续表现为单体的声学行为。在严重的热处理，BSA迅速遭受不可逆的变性和凝胶化发生影响超声衰减光谱和声速，与显着的分子构象变化和/或分子-分子相互作用一致。
The ability of ultrasound spectroscopy to characterise protein denaturation at relatively high concentrations and under conditions found in foods, is examined. Measurement of longitudinal sound velocity against concentration and frequency (20–160 MHz) for the bovine serum albumin monomer at pH 7.0 gave a frequency independent value for molecular compressibility of κ′ = 2.05 × 10−10Pa−1at 25 °C, corresponding to a sound velocity for the BSA molecule of 1920 m s−1. At 160 MHz, the longitudinal sound attenuation in BSA molecules is ∼5200 Np m−1, a factor of 10 higher than in water. The excess attenuation of the solution over water was nearly 90 Np m−1at the highest measured volume fraction of 0.03 (or 3% v/v). Concentration-dependent ultrasound velocity (20–160 MHz) and attenuation (2–120 MHz) spectra were obtained over time for heated bovine serum albumin (BSA) solutions up to 40 mg/mL at neutral pH and at 25 °C. An acoustic scattering model was used which considered the solute molecules as scatterers of ultrasound, to determine the molecules’ sound velocity, compressibility, and attenuation properties. Mild heat treatment caused the molecule to organise into dimers and trimers, without change in sound velocity; implying that there is little or no change in secondary structure. Changes in attenuation spectra correlated with estimated molecular weight as determined through DLS and SEC measurements. During oligomerisation, the BSA molecules continue to behave acoustically as monomers. Under severe heat treatment, BSA rapidly suffered irreversible denaturation and gelation occurred which affected both ultrasound attenuation spectra and the velocity of sound, consistent with significant molecular conformation changes and/or molecule–molecule interactions.