三种氨基酸添加下酶法修饰酪蛋白水解物的ACE抑制活性

采用碱性蛋白酶水解酪蛋白,制备水解度为12.4%、IC50为42.19μg/mL的酪蛋白水解物。在添加外源氨基酸的情况下对水解物进行类蛋白反应修饰,并响应面法研究氨基酸添加量、酶添加量、反应温度及3种氨基酸的影响。结果表明:氨基酸添加量、反应温度、氨基酸种类对修饰反应影响显著,而酶添加量的影响不大;分别添加苯丙氨酸、亮氨酸、缬氨酸制备3个酪蛋白水解物修饰产物,其IC50降低至21.03～25.13μg/mL,表明添加外源氨基酸可提高修饰产物的体外ACE抑制活性,但添加不同氨基酸的影响不显著。

The ACE-inhibitory Activity in Vitro of Casein Hydrolysates Subjected to Enzymatic Modification in the Presence of Three Extrinsic Amino Acids

Casein hydrolysates that had a degree of hydrolysis of 12.4 % and ACE-inhibition with an IC50 value of 42.19 μg/mL were prepared from casein with a protease Alcalase,and then modified by plastein reaction with Alcalase in the presence of three extrinsic amino acids.The effects of the addition level of amino acids,the addition level of Alcalase,reaction temperature and the types of amino acids on the plastein reaction of casein hydrolysates were investigated with response surface methodology.The results indicated that the addition of amino acids,reaction temperature and the types of amino acid added had significant impact on the plastein reaction,while the addition of Alcalase gave little influence.Three modified casein hydrolysates were prepared with suitable conditions and in the presence of phenylalanine,leucine and valine,respectively.Their IC50 values were in range of 21.03 to 25.13 μg/mL,indicating that the ACE-inhibitory activity in vitro of the modified casein hydrolysates was improved significantly by adding amino acids while the types of amino acids were not important to the activity.