Identification and Inhibitory Mechanism of Angiotensin I-Converting Enzyme Inhibitory Peptides Derived from Bovine Hemoglobin.

Angiotensin I-converting enzyme (ACE, EC.3.4.15.1) inhibitory peptide is an efficacious therapy for hypertension. In this study, four dipeptides, TY, FD, FL and FG, were identified from the desalted fraction of bovine hemoglobin hydrolysate, obtained by in vitro simulated gastrointestinal digestion, via liquid chromatography-tandem mass spectrometry (LC-MS/MS). The IC50 value of TY and FL are 96.43 ± 6.17 and 290.66 ± 57.92 μM, respectively. The result of molecular docking indicated that TY occupied the ACE subsite S1 and S1' with a lowest estimated binding energy of -9.96 Kcal/mol, while FL occupied the subsite S5 with a lowest estimated binding energy of -9.37 Kcal/mol. The subsite S1' and S2' are closer to the ACE active center (Zn2+) than S5, and the lowest estimated binding energy of TY is lower than that of FL. This work provided new ACE-inhibitory peptides derived from bovine hemoglobin hydrolysate and explained their inhibitory mechanism.