High blood pressure or hypertension is a condition affecting many individuals and represents a controllable risk factor for cardiovascular diseases such as coronary heart disease and stroke. A non-pharmacological approach to manage these includes the application of food components with antihypertensive activity. Milk protein-derived peptides have been exploited as natural hypotensive agents, namely the peptides {Val-Pro-Pro} {(VPP)} and {Ile-Pro-Pro} {(IPP)}, already commercialized in functional foods as a potential alternative to synthetic drugs. These bioactive peptides inhibit in vitro and in vivo the Angiotensin I-converting enzyme {(ACE)}, a protein with an important role in blood pressure regulation. In this work, we attempted to elucidate the possible mode of interaction between the peptides and {ACE}, including mechanisms of binding to the cofactor Zn2+, and further contrast this with the known mode of inhibition exerted by synthetic drugs {(Captopril}, Enalaprilat and Lisinopril). The bioactive peptide {Ala-Leu-Pro-Met-His-Ile-Arg} {(ALPMHIR)}, also known to inhibit the enzyme {ACE} but with a lower efficiency than {VPP} and {IPP}, was utilized in the docking studies for comparison. It was observed that the best docking poses obtained for {VPP} and {IPP} were located at the {ACE} catalytic site with very high resemblance to the drugs mode of interaction, including the coordination with Zn2+. As for {ALPMHIR}, the best docking poses were located in the narrow {ACE} channel outside the catalytic site, representing higher affinity energies and fewer resemblances with the interaction established by drugs.
{PMID:} 18816584