乙醇-水体系中酪蛋白水解物的类蛋白反应及ACE抑制活性的变化  

Plastein reaction of casein hydrolysates in alcohol-water system and the change of ACE inhibitory activity

作　　者：肖云[1] 许金龙[1] 李铁晶[1] 

机构地区：[1]东北农业大学乳品科学教育部重点实验室,哈尔滨150030

出　　处：《中国乳品工业》2014年第8期12-15,26,共5页China Dairy Industry

基　　金：国家自然科学基金资助(31140009)

摘　　要：采用Neutrase 0.8L蛋白酶水解酪蛋白,制备水解度为13.6%的酪蛋白水解产物,测得其对血管紧张素转化酶(ACE)的体外抑制活性IC50为(46.92±0.27)mg/L。在乙醇溶剂中,利用Neutrase 0.8L蛋白酶对水解物进行类蛋白反应修饰,并研究酶添加量、底物质量分数、反应温度、反应时间和乙醇浓度对修饰反应的影响。在优化条件下的类蛋白反应体系中,游离氨基浓度减少,说明合成反应占优势;酶添加量、底物质量分数、乙醇质量分数对修饰反应的影响显著,而反应时间和温度影响不大。通过单因素实验确定类蛋白反应的最适反应条件为:44%乙醇水溶液、反应温度为40℃,酶添加量为3 kU/g蛋白质、底物质量分数40%、反应时间6.0 h。此条件下,反应体系中游离氨基浓度变化达到202.19μmol/g蛋白质,修饰产物的IC50值降低至(25.96±0.29)mg/L,降低44.7%。Casein hydrolysate were prepared with Nuetrase 0.8 L. The prepared hydrolysate exhibited inhibition on angiotensin-I-converting enzyme（ACE） in vitro, and the inhibitory activity IC50was（46.92±0.27）μg/mL at the degree of hydrolysis of 13.6%. The hydrolysates were modified by plastein reaction with Neutrase 0.8 L in ethanol. The impacts of the amount of enzyme content, substrate concentration, reaction temperature, reaction time and the ethanol concentration were studied by single factor experiments, and the decrease of free amino acid in the reaction system were detected under optimized reaction conditions, which was suggested that synthesis reaction is dominant. The impacts of substrate concentration, amount of enzyme addition, and ethanol concentration were notable, at the same time temperature and time of reaction were not significant. The optimal reaction conditions were determined by single factor experiment： ethanol solution 44%, reaction temperature of 40 °C, enzyme dosage 3 kU/g proteins, substrate concentration40%, reaction time is 6.0 h. Under this condition, the free amino group content in the reaction system reached 202.19 μmol/g protein, the IC50 value of the modified product was（25.96 ± 0.29）μg/mL, decreased by 44.7%.

关 键 词：酪蛋白水解物 乙醇 类蛋白反应 ACE抑制活性 

分 类 号：Q516[生物学—生物化学]