刺参ACE抑制肽制备及降压功效分析

以刺参（Stichopus japonicus）体壁为原料，利用复合蛋白酶对其进行酶解，运用单因素法优化血管紧张素转化酶（angiotensin I-converting enzyme，ACE）抑制肽的酶解制备工艺。获得最佳工艺参数为：料液比1∶6（g/mL）、加酶量0.8%（质量分数）、反应时间6?h、pH?7.0。将酶解产物用3?kDa膜超滤，其中小于3?kDa组分具有较高的ACE抑制活性，IC50为0.8?mg/mL，对ACE表现为非竞争性抑制作用。刺参ACE抑制肽在高温、酸性和碱性条件下均具有较好的稳定性，同时具有较强的抵抗胃蛋白酶、胰蛋白酶和胰凝乳蛋白酶消化的能力。动物实验结果表明，刺参ACE抑制肽对雄性自发性高血压大鼠具有良好的降压功效。因此，利用复合蛋白酶酶解刺参体壁制备的ACE抑制肽在降血压功能性食品的开发利用方面具有研究价值。

Preparation and Antihypertensive Activity of Angiotensin I-Converting Enzyme (ACE) Inhibitory Peptides Derived from Sea Cucumber (Stichopus japonicas)

The body wall of sea cucumber (Stichopus japonicus) was hydrolyzed by protamex proteinase to produce angiotensin I-converting enzyme (ACE) inhibitory peptides. Using one-factor-at-a-time method, the optimum hydrolysis conditions to obtain the highest ACE inhibitory activity were determined as follows: solid to liquid ratio, 1:6 (g/mL); proteinase dosage, 0.8% (m/m); hydrolysis time, 6 h; and hydrolysis pH, 7.0. Ultrafiltration of the resulting hydrolysate yielded a less than 3 kDa fraction with ACE inhibitory activity, whose IC50 was 0.8 mg/mL. Kinetic analysis showed that the inhibitory action of the fraction on ACE was non-competitive. The ACE inhibitory peptides were stable under high temperature, acidic or alkaline conditions and were resistant to gastrointestinal digestion in vitro. Furthermore, these peptides could significantly decrease systolic blood pressure in spontaneously hypertensive rats (SHRs). The present work could provide a theoretical basis for the development of sea cucumber peptides with ACE inhibitory activity as potential antihypertensive food ingredients.