Rational module substitution strategy to enhance ACE-inhibitory peptide activity.

Food-derived angiotensin-converting enzyme (ACE)-inhibitory peptide plays key roles in hypertension prevention, however, their activity is dependent on specific sequence composition. This study aims to enhance peptide activity using a module substitution strategy. Molecular docking and activity assays identified MF as a low- and FP as a high-contribution dipeptide module within MFPWP. To replace the low-contribution module while retaining the high one, alternative "XF" modules were systematically evaluated, revealing CF, TF, VF, and PF as high-contribution modules. Substituting MF with these modules generated CFPWP, TFPWP, VFPWP, and PFPWP which showed 21.30 %-67.07 % higher ACE-inhibition than the original sequence MFPWP, potentially due to increased hydrogen bonding and hydrophobic interactions with ACE. Cellular assays confirmed enhanced antihypertensive effects via greater nitric oxide (NO) release and reduced endothelin-1 (ET - 1) levels. These findings demonstrate that module substitution is an effective approach to improve peptide activity and provide insight into module effect within bioactive peptide sequences.