大豆脂氧酶的热失活动力学与其二级结构的圆二色谱表现

Thermal Inactivation of Soybean Lipoxygenase and Its Secondary Structure Performance of Circular Dichroism Specctroscopy

应用大豆脂氧酶的变温圆二色谱图研究了大豆脂氧酶(LOX)的热失活与二级结构变化过程。结果表明:在50～65℃条件下,10 min内,LOX的酶活随热处理时间延长而下降,其热失活过程遵循一级动力学,活化能Ea值为217 kJ.mol-1。在相同的热处理条件下,LOX中二级结构α-螺旋和β-折叠的相对含量均在20%左右浮动,不符合一级反应动力学,二级结构的变化并非LOX失活的主要原因。

The inactivation and secondary structure variation of soybean lipoxygenase（LOX） during heating process was studied with circular dichroism（CD） spectroscopy.The quantitative secondary structures of LOX at various temperatures were obtained.At 50～65 ℃,LOX activity has a sharp drop with the time prolonging.Thermal inactivation of LOX could be described by a first order kinetic model,and activation energy Ea was further calculated to be 217 kJ·mol-1.During the heating process,the contents of α-helix and β-sheet were both floating at 20%,indicated that the change of secondary structure of LOX was not the main reason for the loss of their activities.