Peptides isolated from black soybean synergistically inhibit the activity of angiotensin converting enzyme (ACE)
B. Shao, Xinyu Huang, Mengdan Xu, Dawei Cheng, Xueling Li, Meiqing Li
Abstract
The main purpose of this study was to isolate and identify Angiotensin Converting Enzyme (ACE) inhibitory peptides (IPs) from black soybean protein hydrolysate and compare the activity between single and mixed peptides. Black soybean protein was hydrolyzed, desalted, and separated by size-exclusion ultrafiltration and G-15 Sephadex column. A total of 31 peptides were identified by nano-HPLC-ESI-MS/MS. 7 peptides were screened by molecular docking, only three were ACEIPs after synthetized and bioactive verified, namely KDFPPR (IC50 = 7.91 ± 0.27 mg/mL), VVPPGHPF (IC50 = 12.13 ± 0.38 mg/mL) and DTFPYPR (IC50 = 10.69 ± 0.28 mg/mL), 3 peptides all show mixed-type mode of enzyme inhibition. The synergistic effect on the inhibition of ACE activity was shown among the three ACEIPs. The other four peptides play an auxiliary role in the activity of three ACEIPs mixtures. This study showed that black soybean protein is a reliable source of ACEIPs and the synergism of natural mixed peptides may play an important role in the activity of bioactive peptides.