食品科学

• 基础研究 • 上一篇    下一篇

苦丁冬青苦丁茶中咖啡酰奎尼酸类物质与牛血清白蛋白的相互作用

徐冬兰,周 莉,胡 冰,孙 怡*,曾晓雄   

  1. 南京农业大学食品科技学院,江苏 南京 210095
  • 出版日期:2015-06-15 发布日期:2015-06-07

Interaction of Caffeoylquinic Acid Derivatives from Ilex kudingcha C. J. Tseng with Bovine Serum Albumin

XU Donglan, ZHOU Li, HU Bing, SUN Yi*, ZENG Xiaoxiong   

  1. College of Food Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
  • Online:2015-06-15 Published:2015-06-07

摘要:

从苦丁冬青苦丁茶中分离纯化得到了4 种咖啡酰奎尼酸(caffeoylquinic acids,CQA):5-CQA、3,4-diCQA、3,5-diCQA和4,5-diCQA,并在模拟人体生理条件(pH 7.4,310 K)下,利用荧光光谱法分析4 种CQA与牛血清白蛋白(bovine serum albumin,BSA)的相互作用,使用修正后的Stern-Volmer方程与van’t Hoff方程探讨CQA-BSA之间的结合常数、结合位点数及热力学参数。结果表明:4 种CQA均能与BSA结合,从而导致BSA分子内部荧光发生猝灭,结合能力的大小顺序为3,4-diCQA>3,5-diCQA>4,5-diCQA>5-CQA,说明咖啡酰基的增多提高了结合能力。热力学参数ΔH>0、ΔS>0和ΔG<0,表明CQA与BSA主要靠疏水作用力结合,反应自发进行。此外,CQA的结合引起BSA 3D荧光光谱和同步荧光光谱的变化,表明两者之间的结合主要是通过与BSA中色氨酸和酪氨酸的作用而实现的。

关键词: 苦丁茶, 咖啡酰奎尼酸, 牛血清白蛋白, 荧光光谱, 相互作用

Abstract:

In the present study, the interactions between bovine serum albumin (BSA) and four caffeoylquinic acid (CQA)
derivatives (5-CQA, 3,4-diCQA, 3,5-diCQA and 4,5-diCQA) isolated from the leaves of Ilex kudingcha C. J. Tseng were
investigated by fluorescence spectroscopy under simulated physiological condition (pH 7.4 and 310 K). The binding
parameters were calculated according to modified Stern-Volmer equation, and the thermodynamic parameters were
determined by the van’t Hoff equation. The results showed that CQA derivatives interacted with BSA, and the binding
constants were ranked in the following order: 3,4-diCQA > 3,5-diCQA > 4,5-diCQA > 5-CQA, suggesting that the addition
of caffeoyl moiety significantly increased the binding capacity. Thermodynamic analysis showed that the ΔH and ΔS values
were both positive and the ΔG was negative, indicating that the interaction process was spontaneous, and hydrophobic
force might be primarily responsible for the interaction. In addition, the conformational change of BSA was observed by
3D fluorescence and synchronous fluorescence spectra, indicating that the interaction between CQA and BSA was achieved
through the binding of CQA to the tryptophan and tyrosine residues of BSA.

Key words: Kudingcha, caffeoylquinic acid, bovine serum albumin, fluorescence spectroscopy, interaction

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