Affinity Purification and Molecular Characterization of Angiotensin-Converting Enzyme (ACE)-Inhibitory Peptides from Takifugu flavidus
Yongchang Su, Shicheng Chen, Shuji Liu, Wang Yin, Xiaoting Chen, Min Xu, Shuilin Cai, Nan Pan, Kun Qiao, Bei Chen, Suping Yang, Zhiyu Liu
Abstract
An affinity chromatography filler of CNBr-activated Sepharose 4B-immobilized ACE was used to purify ACE-inhibitory peptides from Takifugu flavidus protein hydrolysate (<1 kDa). Twenty-four peptides with an average local confidence score (ALC) ≥ 80% from bounded components (eluted by 1 M NaCl) were identified by LC-MS/MS. Among them, a novel peptide, TLRFALHGME, with ACE-inhibitory activity (IC50 = 93.5 µmol·L−1) was selected. Molecular docking revealed that TLRFALHGME may interact with the active site of ACE through H-bond, hydrophobic, and electrostatic interactions. The total binding energy (ΔGbinding) of TLRFALHGME was estimated to be −82.7382 kJ·mol−1 by MD simulations, indicating the favorable binding of peptides with ACE. Furthermore, the binding affinity of TLRFALHGME to ACE was determined by surface plasmon resonance (SPR) with a Kd of 80.9 µmol, indicating that there was a direct molecular interaction between them. TLRFALHGME has great potential for the treatment of hypertension.