黑木耳多糖对胰脂肪酶活性的抑制作用
Inhibitory effect of Auricularia auricula polysaccharides on pancreatic lipase activity
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摘要: 目的:以月桂酸4-硝基苯酯为底物,考察黑木耳多糖对胰脂肪酶活性的抑制作用,确定最佳抑制条件、抑制类型及抑制常数。方法:采用水提醇沉的方法制备黑木耳多糖,阴离子交换树脂分离多糖,考察不同反应条件（浓度、p H、温度、时间）下黑木耳多糖各组分对胰脂肪酶活性的抑制效果;通过紫外吸收光谱研究黑木耳多糖与胰脂肪酶构象之间的关系;测定不同浓度底物时的反应吸光度值,初步确定黑木耳多糖对胰脂肪酶抑制作用的机理。结果:分离获得6个组分,其中中性多糖组分a对胰脂肪酶抑制效果较好。当p H为7.5、温度37℃、反应时间为60 min时抑制效果最佳,此时中性多糖组分a抑制率最高达到46.93%;反应类型为非竞争性抑制,米氏常数Km为17.68 mg/m L,最大反应速率Vmax为1.43μmol/min,抑制常数Ki为30.32 mg/m L。通过紫外吸收光谱测定,胰脂肪酶最大吸收波长发生红移,说明黑木耳多糖改变了胰脂肪酶的构象,致使其酶催化活性受到抑制。结论:黑木耳多糖对胰脂肪酶活性具有抑制作用,表明黑木耳多糖降血脂作用可能与胰脂肪酶的活性抑制有关,为降血脂功能性产品的开发奠定理论基础。Abstract: Objective:The inhibitory effect of Auricularia auricula polysaccharides on the activity of pancreatic lipase was investigated.4-nitrophenyl laurate was used as a substrate.To screening optimum conditions of Auricularia auricula polysaccharides inhibited of the pancreatic lipaseactivity, the types of inhibition and inhibition of constant.Methods:Auricularia auricula polysaccharides were obtained through hot water extraction and alcohol precipitation.Polysaccharides were separated by anion exchange resin.The effects of Auricularia auricula polysaccharides were studied under different conditions (concentrate, p H, temperature, time) on pancreatic lipase activity.The relation between Auricularia auricular polysaccharides and conformation of pancreatic lipase were researched through ultraviolet absorption spectrometry.The reaction mechanism of between Auricularia auricula polysaccharides and pancreatic lipase through testing absorbance values was ensured when added different concentrate substrates.Results:Six components were obtained, and the neutral polysaccharide had the best suppression effect.When the p H was 7.5, temperature was 37℃, and time was 60 minutes, the inhibition rate reached the maximum value46.93%.And the reaction was a noncompetitive inhibition.The Michaelis constant was 17.68 mg/m L.The maximum reaction rate was 1.43μmol/min.The Ki was 30.32 mg/m L.By ultraviolet absorption spectrometry it showed that pancreatic lipase maximum absorption wavelength ultraviolet absorption spectrum redshift, which meant the Auricularia auricula polysaccharide changed the conformation of pancreatic lipase, leading to the restriction of enzyme catalytic activity.Conclusion:Auricularia auricula polysaccharides had suppression effect on pancreatic lipase activity.It indicated that the antihyperlipidemic effect of Auricularia auricula polysaccharide was related with the inhibiton of the activity of pancreatic lipase, which lay a theoretical foundation for the development of the functional products of reducing blood lipid.
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