食品科学 ›› 2019, Vol. 40 ›› Issue (16): 1-7.doi: 10.7506/spkx1002-6630-20180926-279

• 食品化学 •    下一篇

温度、pH值对离体模型中肌原纤维蛋白去磷酸化反应的影响

任 驰,侯成立,李 欣,摆玉蔷,张德权   

  1. 中国农业科学院农产品加工研究所,农业部农产品加工重点实验室,北京 100193
  • 出版日期:2019-08-25 发布日期:2019-08-26
  • 基金资助:
    国家自然科学基金面上项目(31471604);国家农业科技创新工程项目(CAAS-ASTIP-2016-IFST)

Effect of Temperature and pH on Dephosphorylation of Myofibrillar Protein in Vitro

REN Chi, HOU Chengli, LI Xin, BAI Yuqiang, ZHANG Dequan   

  1. Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Products Processing, Ministry of Agriculture, Beijing 100193, China
  • Online:2019-08-25 Published:2019-08-26

摘要: 研究温度(25、15 ℃和4 ℃)和pH值(5.2、5.8、6.4)对碱性磷酸酶活性及催化去磷酸化反应能力的影响,为改善肉品质提供理论依据。提取宰后羊肉中的肌原纤维蛋白建立离体模型,添加碱性磷酸酶催化肌原纤维蛋白发生去磷酸化反应。采用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、Pro-Q Diamond磷酸化蛋白染色和SYPRO Ruby全蛋白染色测定肌原纤维蛋白磷酸化水平,试剂盒测定碱性磷酸酶活性。结果表明,随着孵育时间延长,pH 5.8和pH 6.4条件下碱性磷酸酶组肌原纤维蛋白磷酸化水平显著下降(P<0.05),pH 5.2条件下碱性磷酸酶组肌原纤维蛋白磷酸化水平无显著变化(P>0.05)。对照组肌原纤维蛋白磷酸化水平在整个孵育期间无显著变化(P>0.05);4 ℃、pH 5.2条件下显著抑制(P<0.05)碱性磷酸酶活性,使其催化去磷酸化时间延迟。测定碱性磷酸酶磷酸化水平发现,碱性磷酸酶不仅可以催化肌原纤维蛋白发生去磷酸化反应,也能催化其自身发生去磷酸化反应,且碱性磷酸酶自身发生去磷酸化后不会失活。因此在一定范围内升高温度和pH值会提高碱性磷酸酶催化底物去磷酸反应的能力,降低磷酸化水平,且使去磷酸化时间提前,为改善肉品质及肉贮藏提供新思路。

关键词: 蛋白质磷酸化, 碱性磷酸酶, 去磷酸化, 温度, pH值

Abstract: This study determined the effect of temperature (25, 15, and 4 ℃) and pH (5.2, 5.8, and 6.4) on dephosphorylation of myofibrillar protein, aiming to provide a theoretical basis for improving meat quality. Myofibrillar protein from postmortem muscle was extracted and alkaline phosphatase (AP) was added to catalyze its dephosphorylation. The phosphorylation level was detected by sodium dodecyl sulfate-polyacrymyl gel electrophoresis (SDS-PAGE) followed by sequential fluorescence staining of the gels using Pro-Q Diamond and SYPRO Ruby. Moreover, AP activity was measured by a commercial kit. The results demonstrated that at pH 5.8 and 6.4, the phosphorylation level of myofibrillar protein in the AP group significantly decreased with the prolongation of incubation (P < 0.05), while no significant change occurred at pH 5.2 (P > 0.05). Likewise, the control group showed no significant change in the phosphorylation level of myofibrillar protein throughout the incubation period (P > 0.05). At 4 ℃ and pH 5.2, AP activity was inhibited, delaying the catalytic time (P < 0.05). Interestingly, AP catalyzed not only the dephosphorylation of myofibrillar protein but also its own dephosphorylation, which caused no loss of activity. Increasing temperature and pH in a certain range could promote the dephosphorylation ability of AP, thereby decreasing the phosphorylation level of myofibrillar protein and making the reaction start earlier. These findings can be important for improving meat quality and provide a new idea for meat preservation.

Key words: protein phosphorylation, alkaline phosphatase, dephosphorylation, temperature, pH

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