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目的:体外模仿部分胃肠道消化酶解过程,考察大豆蛋白酶解消化能否产生血管紧张素转化酶抑制剂(ACEI)活性肽及其活性状况,以揭示大豆蛋白体内消化酶解与ACEI的活性关系。方法:模拟人体胃肠道消化过程,以胃蛋白酶结合胰蛋白酶,相继酶解大豆分离蛋白(SPI),经色谱分离,动态检测不同阶段ACEI肽片段及其活性大小。结果:胃蛋白酶酶解过程前20min内,酶解液ACEI活性达到最高点,随后在胰蛋白酶酶解阶段其抑制活性下降。180min后的酶解产物,其半抑制活性浓度IC50值为0.28±0.06 mg/ml。同时,未经酶解的SPI液在0.73mg/ml时无ACEI活性。SPI酶解液经各种色谱分离后的组分,其IC50值从0.13±0.03到0.93±0.08 mg/ml。低分子量和伴有疏水性基团的肽类最具ACE抑制活性。结论:体外模仿胃肠消化过程使用胃蛋白酶和胰蛋白酶酶解SPI可产生不同ACEI活性的肽片段,说明人体正常摄食消化大豆蛋白可产生血管紧张素转化酶抑制剂活性肽。
OBJECTIVE: To mimic partial gastrointestinal digestion and enzymatic hydrolysis in vitro and investigate whether soy protein digestion can produce ACEI peptide and its activity, so as to reveal the enzymatic digestion and ACEI activity of soy protein in vivo relationship. Methods: The digestive process of human gastrointestinal tract was simulated. Pepsin and trypsin were combined to digest soy protein isolate (SPI) one after another. Chromatographic separation was used to detect the activity of ACEI peptide fragments at different stages. Results: During the first 20 min of pepsin digestion, the ACEI activity reached the highest point, and then its inhibitory activity decreased during trypsin digestion. After 180min, the half-inhibitory concentration (IC50) was 0.28 ± 0.06 mg / ml. Meanwhile, un-digested SPI solution had no ACEI activity at 0.73 mg / ml. The components of SPI hydrolysates separated by various chromatographic methods showed IC50 values from 0.13 ± 0.03 to 0.93 ± 0.08 mg / ml. Peptides with low molecular weight and hydrophobic groups have the most ACE inhibitory activity. CONCLUSION: Peptide fragments with different ACEI activity can be produced by digestion of pepsin and trypsin in vitro during gastrointestinal digestion, indicating that human normal intake of digested soy protein can produce angiotensin-converting enzyme inhibitor active peptide.