Sava N, Van der Plancken I, Claeys W, Hendrickx M
Department of Bioengineering, Faculty of Food Science and Engineering, Dunarea de Jos University, Domneasca 111, 800201 Galati, Romania.
J Dairy Sci. 2005 May;88(5):1646-53. doi: 10.3168/jds.S0022-0302(05)72836-8.
Heat-induced structural changes of beta-lactoglobulin were studied at temperatures ranging from 67.5 to 82.5 degrees C, and at pH 7.5. These changes were monitored by measurement of surface hydrophobicity, thiol availability, and protein solubility. Kinetic studies were conducted to quantitatively describe the contribution of hydrophobic and SH/SS interchange reactions to the thermal structural changes of beta-lactoglobulin. Results indicate that beta-lactoglobulin is sensitive to heat-induced interchange reactions with consequences for protein solubility. The extent of changes measured by the increase in surface hydrophobicity and the decrease in slow-reacting SH groups content could be described by a first-order fractional conversion model and were characterized by activation energy values of 233.9 +/- 8.6 and 148.2 +/- 6.7 kJ/mol, respectively. The break in the Arrhenius plot suggested in literature for beta-lactoglobulin denaturation was confirmed in this study only for the kinetics of exposed SH groups.
在67.5至82.5摄氏度的温度范围以及pH值为7.5的条件下，研究了热诱导β-乳球蛋白的结构变化。通过测量表面疏水性、巯基可用性和蛋白质溶解度来监测这些变化。进行动力学研究以定量描述疏水和SH/SS交换反应对β-乳球蛋白热结构变化的贡献。结果表明，β-乳球蛋白对热诱导的交换反应敏感，这会影响蛋白质的溶解度。通过表面疏水性增加和慢反应SH基团含量减少来衡量的变化程度可以用一级分数转化模型来描述，其特征在于活化能值分别为233.9±8.6和148.2±6.7kJ/mol。本研究仅在暴露的SH基团动力学方面证实了文献中所提出的β-乳球蛋白变性的阿累尼乌斯图中的断点。
