食品科学 ›› 2018, Vol. 39 ›› Issue (14): 1-8.doi: 10.7506/spkx1002-6630-201814001

• 食品化学 •    下一篇

原子力显微镜研究L-半胱氨酸对鲢肌球蛋白溶液热聚集行为的影响

王艳敏,于加美,石彤,袁丽,高瑞昌*   

  1. (江苏大学食品与生物工程学院,江苏?镇江 212013)
  • 出版日期:2018-07-25 发布日期:2018-07-16
  • 基金资助:
    国家自然科学基金面上项目(31471611;31671882);现代农业产业技术体系建设专项(CARS-46)

Influence of L-Cysteine on the Heat-Induced Aggregation of Bighead Carp Myosin Studied by Atom Force Microscope

WANG Yanmin, YU Jiamei, SHI Tong, YUAN Li, GAO Ruichang*   

  1. (School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China)
  • Online:2018-07-25 Published:2018-07-16

摘要: 利用原子力显微镜技术分析L-半胱氨酸(L-cysteine,L-Cys)对鲢肌球蛋白热聚集行为的影响。在肌球蛋白溶液中添加5?mmol/L(pH?7.0)的L-Cys溶液,分别进行未加热(25?℃、30?min)、一段式加热(90?℃、30?min)、二段式加热(40?℃、60?min+90?℃、30?min)处理,分别测定溶解度、表面疏水性、聚集行为表面形貌的变化。结果表明:3?种加热方式低盐条件下L-Cys均显著提高肌球蛋白的溶解度(P<0.05);一段式加热时L-Cys显著提高高/低盐条件下肌球蛋白的表面疏水性(P<0.05),二段式加热时高盐条件下表面疏水性显著提高(P<0.05),其他条件下表面疏水性无明显变化。高/低盐条件下添加L-Cys均能显著改变肌球蛋白聚集行为的表面形貌,使聚集体更加分散,抑制了肌球蛋白的聚集。L-Cys对肌球蛋白溶解度、表面疏水性的影响进一步影响了其聚集行为,改变其聚集形貌。

关键词: 半胱氨酸(L-Cys), 原子力显微镜, 肌球蛋白, 表面形貌

Abstract: The effect of L-cysteine on the heat-induced aggregation behavior of bighead carp myosin was studied using atomic force microscope (AFM). Changes in the solubility, surface?hydrophobicity and aggregate surface morphology of myosin samples with 5 mmol/L (pH 7.0) L-Cys added were measured after being treated at 25 ℃ for 30 min (control), at 90 ℃ for 30 min (one-step heating) or at 40 ℃ for 60 min and then at 90 ℃ for another 30 min (two-step heating). The results showed that L-Cys significantly increased the solubility of myosin in low ionic strength solutions under all three heating modes (P < 0.05). Under both high and low ionic strength conditions, the surface hydrophobicity increased significantly in the presence of L-Cys after one-step heating (P < 0.05), whereas for two-step heating, it increased significantly only under high ionic strength conditions (P < 0.05). Under both high and low ionic strength conditions, added L-Cys remarkably altered the surface morphology of myosin aggregates, loosening the aggregates and inhibiting aggregation. Conclusively, L-Cys affects the solubility and surface hydrophobicity of fish myosin, thereby affecting the aggregation behavior and altering the aggregate morphology.

Key words: L-cysteine, atomic?force?microscope (AFM), myosin, morphology

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