Key Laboratory of Meat Processing and Quality Control, Ministry of Education China, College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
Traditional Food Processing and Machinery Laboratory, Institute of Agro-Products Processing Science and Technology, Chinese Academy of Agricultural Science, Beijing 100193, China.
Food Chem. 2014 May 1;150:220-6. doi: 10.1016/j.foodchem.2013.10.149. Epub 2013 Nov 1.
This study was designed to investigate the effects of desmin oxidation on its degradation by proteolytic enzymes. Desmin was isolated from bovine muscle and exposed to varying oxidative conditions, and then incubated with μ-calpain, caspase-3 or -6, respectively. The extent of protein degradation was subsequently determined using SDS-PAGE and Western-blotting. Furthermore, the oxidative modification of the secondary structure of desmin was measured by circular dichroism (CD). Our results revealed that, compared with the native desmin, degradation of oxidised desmin was enhanced by caspases, but suppressed by μ-calpain. The CD spectra of desmin showed that the content of α-helix decreased from 76.2% to 52% while random coil increased from 8% to 22.4% after oxidation. These findings demonstrated that oxidative modifications of desmin changed their susceptibility to μ-calpain, caspase-3 and -6 as well as their secondary structure.
本研究旨在探讨中间丝蛋白desmin 氧化对其被蛋白水解酶降解的影响。从牛肌肉中分离出 desmin，使其分别处于不同的氧化条件下，然后与 μ-钙蛋白酶、caspase-3 或 caspase-6 孵育。随后使用 SDS-PAGE 和 Western-blotting 测定蛋白降解的程度。此外，还通过圆二色性（CD）测量了 desmin 二级结构的氧化修饰。我们的结果表明，与天然 desmin 相比，氧化修饰的 desmin 被 caspase 降解的程度增强，但被 μ-钙蛋白酶抑制。desmin 的 CD 图谱显示，氧化后α-螺旋的含量从 76.2%下降到 52%，而无规卷曲从 8%增加到 22.4%。这些发现表明，desmin 的氧化修饰改变了其对 μ-钙蛋白酶、caspase-3 和 caspase-6 的敏感性以及二级结构。
