两种来源于牛皮胶原蛋白的新型ACE抑制肽

从牛皮胶原蛋白中鉴定分离出抑制血管紧张素Ⅰ转换酶（ACE）的多肽片段。首先优化牛皮胶原蛋白水解方法,应用胃蛋白酶和碱性蛋白酶获得活性最高的水解产物（抑制ACE的IC50为0.168 mg/m L）。经MW 5000超滤分离后,得到水解液中活性最高的部分（IC50为0.079 mg/m L）。对分离后低于MW 5000的部分经RP-HPLC进一步分离,发现含有大量ACE抑制肽,并应用RP-HPLC-MS/MS鉴定出两种新型ACE抑制肽,氨基酸序列分别为ISVPGPM和LGPVGNPGPA,IC50值分别为0.017 mg/m L（24.3μmol/L）和0.077 mg/m L（87.8μmol/L）。最后,本文模拟了两种抑制肽在体内生理环境下的消化,发现均可被部分降解,且消化产物具有与原始多肽相近的ACE抑制活性。 

Two novel ACE inhibitory peptides derived from bovine skin collagen

Peptidic fractions which inhibit angiotensin I-converting enzyme ( ACE) were identified from bovine skin collagen.First, bovine skin collagen was hydrolyzed by an optimized method using pepsin and alcalase.Hydrolyzed collagen obtained the most active hydrolysate ( inhibitory against ACE with an IC50 of 0.168 mg/m L) . With an ultrafiltration by MW 5000, the most active fraction of the hydrolysate was obtained ( IC50 of 0.079 mg/m L) .After further separations with the fraction lower than MW5000 by RP-HPLC, considerable ACE inhibitory peptides were found. Two novel ACE inhibitory were identified by RP-HPLC-MS/MS. The amino acid sequences were ISVPGPM and LGPVGNPGPA, IC50 values of 0.017 mg/m L ( 24.3 μmol/L) and 0.077 mg/m L ( 87.8 μmol/L) , respectively.Finally, the digestion of the two peptides in vivo physiological environment was simulated and both of them were partly degraded. The ACE inhibitory activity of the digestive products were similar to the original polypeptides.