Purification, Characterization and Mechanistic Evaluation of Angiotensin Converting Enzyme Inhibitory Peptides Derived from Zizyphus Jujuba Fruit

Mina Memarpoor-Yazdi,Hadi Zare-Zardini,Navid Mogharrab,Leila Navapour

doi:10.1038/s41598-020-60972-w

Abstract

The synthetic Angiotensin Converting Enzyme (ACE) inhibitors have side effects and hence demands for natural ACE inhibitors have been rising. The aim of this study is to purify and introduce natural ACE inhibitors extracted from Zizyphus jujuba fruits. Proteins from Zizyphus jujuba were lysed by trypsin, papain and their combination. Acquired peptides were purified and evaluated for ACE inhibitory activity. Peptide fractions with inhibitory activity were sequenced using tandem mass spectrometry. To elucidate the mode of peptide binding to ACE, homology modeling, molecular docking and molecular dynamics simulation were performed. Amino acid sequence of F2 and F4 peptides, which were the most active hydrolysates, were determined to be IER and IGK with the IC50 values of 0.060 and 0.072 mg/ml, respectively. Results obtained by computational analysis revealed that similar to the common ACE competitive inhibitors such as captopril, IER tripeptide binds to the enzyme active site, in vicinity of the zinc binding site, and occupies the S1 and S2’ subsites. Binding occurs through hydrogen bonding with Gln293, Lys522, His524, Tyr531 and also several hydrophobic interactions. Collectively, these findings indicate that IER tripeptide inhibits the rabbit ACE enzyme through a competitive mechanism of inhibition with IC50 values in the millimolar range.

Highlights

Angiotensin Converting Enzyme (ACE) inhibitory peptides are the best known amongst various classes of regulatory bioactive peptides due to the development of functional foods with homeostasis role in the human body[3]
As a complement to our experiment, homology modeling, molecular docking and 100 nanoseconds molecular dynamics (MD) simulation were performed to provide an atomistic insight into the interaction of IER peptide with the ACE
Proteins extracted from Z. jujuba fruits were used to purify ACE inhibitory peptides

Summary

Introduction

ACE inhibitory peptides are the best known amongst various classes of regulatory bioactive peptides due to the development of functional foods with homeostasis role in the human body[3]. Several ACE inhibitory peptides have been reported from hydrolysis of different food proteins, such as hen egg white lysozyme[4], fish[6], corn[7], soybean[8], milk[9], casein[10], etc. These peptides are good candidates to regulate blood pressure and to balance fluid and electrolytes in mammals. There are several reports on the presence of different bioactive compounds in this plant, there is no evidence indicating the presence of ACE inhibitory peptides. As a complement to our experiment, homology modeling, molecular docking and 100 nanoseconds (ns) molecular dynamics (MD) simulation were performed to provide an atomistic insight into the interaction of IER peptide (due to the higher affinity) with the ACE

Objectives

Methods

Results

Conclusion