The molecular mechanisms of interactions between bioactive peptides and angiotensin-converting enzyme

The ability of milk protein derived Ile-Pro-Ala (IPA), Phe-Pro (FP) and Gly-Lys-Pro (GKP) peptides to inhibit angiotensin I-converting enzyme (ACE), a protein with an important role in blood-pressure regulation, were verified in vitro and in vivo. This work elucidates the modes and molecular mechanisms of the interaction of IPA, FP and GKP with ACE, including mechanisms that bind the peptides to the cofactor Zn(2+). It was observed that the best docking poses obtained for IPA, FP and GKP were at the ACE catalytic site with very similar modes of interaction, including the interaction with Zn(2+). The interactions, including H-bonds, hydrophobic, hydrophilic, and electrostatic interactions, as well as the interaction with Zn(2+), were responsible for the binding between the bioactive peptides and ACE.