食品科学 ›› 2017, Vol. 38 ›› Issue (15): 1-6.doi: 10.7506/spkx1002-6630-201715001

• 基础研究 •    下一篇

肌原纤维蛋白磷酸化对其被μ-钙蛋白酶降解的影响

李铮,李欣,杜曼婷,李蒙,张德权   

  1. (中国农业科学院农产品加工研究所,农业部农产品加工综合性重点实验室,北京 100193)
  • 出版日期:2017-08-15 发布日期:2017-09-06
  • 基金资助:
    国家自然科学基金面上项目(31471604);中国博士后科学基金面上项目(2015M571176);国家现代农业(肉羊)产业技术体系建设专项(CARS-39)

Effect of Phosphorylation on the Degradation of Myofibrillar Proteins by μ-Calpain

LI Zheng, LI Xin, DU Manting, LI Meng, ZHANG Dequan   

  1. (Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, China)
  • Online:2017-08-15 Published:2017-09-06

摘要: 目的:研究肌原纤维蛋白磷酸化对其被μ-钙蛋白酶降解的影响。方法:以羊背最长肌肌原纤维蛋白为原料,添加蛋白激酶A和碱性磷酸酶催化磷酸化和去磷酸化反应,反应后加入μ-钙蛋白酶,通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE)和荧光染色、蛋白质免疫印迹测定肌原纤维蛋白的磷酸化水平、蛋白降解程度。结果:蛋白激酶A处理组肌原纤维蛋白磷酸化水平显著高于对照组(P<0.05);碱性磷酸酶处理组肌原纤维蛋白磷酸化水平显著低于对照组(P<0.05);蛋白激酶A处理抑制μ-钙蛋白酶自溶,降低其活性,延长其发挥活性的时间;蛋白激酶A处理促进肌球蛋白重链及肌钙蛋白T降解;碱性磷酸酶处理促进肌动蛋白及肌间线蛋白降解。结论:磷酸化通过作用于μ-钙蛋白酶活性及肌原纤维蛋白进而影响μ-钙蛋白酶降解肌原纤维蛋白。

关键词: 磷酸化, 肌原纤维蛋白, μ-钙蛋白酶, 降解, 蛋白激酶A, 碱性磷酸酶

Abstract: Objective: The objective of this study was to investigate the effect of phosphorylation on the degradation of myofibrillar proteins by μ-calpain. Methods: Protein kinase A (PKA) and alkaline phosphatase (AP) were used to catalyze the phosphorylation and dephosphorylation of myofibrillar proteins of mutton longissimus dorsi muscle, followed by hydrolysis by μ-calpain. The levels of protein phosphorylation and degradation were measured by SDS-PAGE, Pro-Q Diamond fluorescent staining, and Western blotting, respectively. Results: The phosphorylation level of myofibrillar proteins in the PKA group was significantly higher than that of the control group (P < 0.05), while the phosphorylation level of myofibrillar proteins in the AP group was significantly lower than that of the control group (P < 0.05). The autolysis and activity of μ-calpain were suppressed by PKA treatment, thereby leading to prolonged hydrolysis of myofibrillar proteins by μ-calpain. Phosphorylation enhanced the degradation of myosin heavy chain and troponin T, while dephosphorylation enhanced the degradation of actin and desmin. Conclusion: Phosphorylation affected both myofibrillar proteins and μ-calpain activity and therefore the degradation of myofibrillar proteins by μ-calpain.

Key words: phosphorylation, myofibrillar proteins, μ-calpain, degradation, protein kinase A, alkaline phosphatase

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