低离子强度下调节pH值对鲤肌球蛋白空间构象的影响  

Effect of Regulation pH on the Conformation of Myosin from Common Carp at Low Ionic Strength

作　　者：田元勇 王伟 宋扬 刘俊荣 Tian Yuanyong;Wang Wei;Song Yang;Liu Junrong(College of Food Science and Engineering, Dalian Ocean University, Dalian 116023, Liaoning)

机构地区：[1]大连海洋大学食品科学与工程学院,辽宁大连116023

出　　处：《中国食品学报》2019年第3期86-92,共7页Journal of Chinese Institute Of Food Science and Technology

基　　金：国家自然科学基金面上项目(31271980)

摘　　要：探讨了低离子强度(0.05 mol/L KCl)条件下,调节pH对鲤肌球蛋白空间构象的影响。试验结果表明:肌球蛋白于酸性pH(2.5,3.5)或碱性pH(11.5,12.5)处理后,溶解度均达到90%以上。pH调节处理后,肌球蛋白Ca^(2+)-ATPase完全失活,即使调回中性也无法恢复,说明肌球蛋白头部结构遭到破坏。圆二色谱分析发现α-螺旋含量没有变化,表明pH调节处理对肌球蛋白尾部二级结构没有影响。此外,经不同pH条件下的酸、碱处理,肌球蛋白的色氨酸荧光发生淬灭,表面疏水性升高,巯基含量降低,胰凝乳蛋白酶酶切位点发生改变,这些都表明肌球蛋白的三级结构遭到破坏。In this study, the effect of pH-shift on the conformation of myosin from common carp at low ionic strength was investigated. The results showed that the solubility of the myosin was over 90% at low ionic strength(0.05 mol/L KCl) and extreme acid-Alkali conditions(pH 2.5, pH 3.5, pH 11.5 and pH 12.5). After pH treatment, the Ca2+-ATPase in myosin was inactivated completely, and the recovery was impracticable even if at neutral pH again, it suggested that the head structure of myosin was already devastated. Circular dichroismspectroscopy analysis showed that the content of α-helix scarcely changed, which indicated that pH treatment had no effect on the tail structure of myosin.And we also found that after the process of different pH treatment, the tryptophan fluorescence of myosin was quenched,the surface hydrophobicity was increased, the sulfhydryl content was decreased and a change was induced at chymotrypsin cleavage sites, which indicated that the tertiary structure of myosin was changed.

关 键 词：鲤肌球蛋白 PH调节 空间构象改变 酶切位点 

分 类 号：TS254.1[轻工技术与工程—水产品加工及贮藏工程]