超临界二氧化碳条件下LOX酶分子的特性及其构象影响

Molecular Properties and Conformational Changes of Lipoxygenase Under Supercritical Carbon Dioxide

在超临界二氧化碳(SCCO2)条件下,在35℃和65℃下,对脂肪氧合酶(LOX)进行处理,用透射电镜(TEM)、SDS-PAGE电泳、圆二色谱(CD)和荧光光谱对处理后的LOX酶的分子形态、一级结构、二级结构和三级结构变化进行了分析表征。实验结果显示:LOX酶蛋白直径变大,可能是酶蛋白分子发生了聚合反应;LOX酶一级结构未发生变化;α-螺旋相对含量降低至6.45%,表明LOX酶的二级结构遭到破坏;LOX的荧光光谱图发生变化,表明LOX酶的三级结构也发生了变化。实验结果表明:在超临界二氧化碳(SCCO2)和加热协同作用下,可以达到对脂肪氧合酶(LOX)一定的灭活作用,以上结果可为SCCO2钝化酶机理的深入研究,以及推动该项技术在食品及其他相关工业中的应用提供理论依据。

Alterations of molecular properties and structure of lipoxygenase （LOX） induced by supercritical carbon dioxide （SCCO2） and 35℃.65℃ temperature synergistic treatment were analyzed using transmis- sion electronic microscope （TEM）,SDS-PAGE, far UV-circular dichroism （CD） and fluorescence spectroscopy. It was shown that the aggregation of PPO molecules was suggested by an increase in the particle size of LOX after SCCO2 treatment, but the electrophoretic behavior of LOX was not altered on the SDSPAGE. The CD and fluorescence spectra of SCCO2-treated LOX were noticeably changed,its α-helix relative content decreased sharply to 6.45 %, and its intrinsic relative fluorescence intensity （RFI） decreased linearly with increasing pressures. This investigation is beneficial for the understanding of the mechanism and to promoting the application of SCCO2 technology in food and other industries.