The vasoconstricting effect of angiotensin II (Ang II) is mediated by Ang II type I receptor (AT1R); blocking or blunting AT1R is a key strategy for the development of antihypertensive drugs. Our previous study showed that the blood pressure lowering the activity of egg white hydrolysate (EWH) in spontaneously hypertensive rats was due to the downregulation of aortic AT1R expression, which promoted us to further identify the AT1R downregulating peptides in the present study. The protein expression of AT1R in a rat aortic vascular smooth muscle cell line A7r5 cells was used for the activity test. The hydrolysate was fractionated stepwise by C18 Sep‐Pack cartridge and reverse‐phase chromatography, and the peptide sequences were characterized by LC‐MS/MS. Peptides including ITKPNDVYS, VVGSAEAGVDAAS, AVHAAHAEINEAGRE, AGREVVGSAEAGVD, and VVGSAEAGVD, were identified. ITKPNDVYS showed the most potent peptide for lowering the level of AT1R in A7r5 cells. These results suggested that ITKPNDVYS is the responsible peptide for lowering the AT1R level in EWH.

中文翻译：

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从蛋清水解物中纯化和鉴定血管紧张素II型I受体下调肽。

血管紧张素II（Ang II）的血管收缩作用是由Ang II I型受体（AT1R）介导的。阻断或钝化AT1R是开发降压药的关键策略。我们以前的研究表明，血压降低自发性高血压大鼠卵清蛋白水解物（EWH）的活性是由于主动脉AT1R表达的下调，这促使我们在本研究中进一步鉴定AT1R下调的肽。将AT1R在大鼠主动脉血管平滑肌细胞系A7r5细胞中的蛋白表达用于活性测试。通过C18 Sep-Pack柱和反相色谱逐步分馏水解产物，并通过LC-MS / MS对肽序列进行表征。肽包括ITKPNDVYS，VVGSAEAGVDAAS，AVHAAHAEINEAGRE，AGREVVGSAEAGVD和VVGSAEAGVD，被确定。ITKPNDVYS显示出降低A7r5细胞中AT1R水平最有效的肽。这些结果表明，ITKPNDVYS是降低EWH中AT1R水平的负责肽。