Journal Article

Preparation and Identification of ACE Inhibitory Peptides from the Marine Macroalga Ulva intestinalis

Sun, Siqi, Zhang, Xiaoqian, Sun, Xue, Xu, Xiaoting, Chen, Xinping, Xu, Nianjun

2019

Overview

Angiotensin I-converting enzyme (ACE) inhibitory peptides derived from seaweed represent a potential source of new antihypertensive. The aim of this study was to isolate and purify ACE inhibitory peptides (ACEIPs) from the protein hydrolysate of the marine macroalga Ulva intestinalis. U. intestinalis protein was hydrolyzed by five different proteases (trypsin, pepsin, papain, α-chymotrypsin, alcalase) to prepare peptides; compared with other hydrolysates, the trypsin hydrolysates exhibited the highest ACE inhibitory activity. The hydrolysis conditions were further optimized by response surface methodology (RSM), and the optimum conditions were as follows: pH 8.4, temperature 28.5 °C, enzyme/protein ratio (E/S) 4.0%, substrate concentration 15 mg/mL, and enzymolysis time 5.0 h. After fractionation and purification by ultrafiltration, gel exclusion chromatography and reverse-phase high-performance liquid chromatography, two novel purified ACE inhibitors with IC50 values of 219.35 μM (0.183 mg/mL) and 236.85 μM (0.179 mg/mL) were obtained. The molecular mass and amino acid sequence of the ACE inhibitory peptides were identified as Phe-Gly-Met-Pro-Leu-Asp-Arg (FGMPLDR; MW 834.41 Da) and Met-Glu-Leu-Val-Leu-Arg (MELVLR; MW 759.43 Da) by ultra-performance liquid chromatography-tandem mass spectrometry. A molecular docking study revealed that the ACE inhibitory activities of the peptides were mainly attributable to the hydrogen bond and Zn(II) interactions between the peptides and ACE. The results of this study provide a theoretical basis for the high-valued application of U. intestinalis and the development of food-derived ACE inhibitory peptides.

• Publisher: MDPI AG,MDPI
• Subject: ACE inhibitory peptide / Algae / Amino acid sequence / Amino acid sequences / Amino acids / Angiotensin I / Angiotensin-converting enzyme inhibitors / Angiotensin-Converting Enzyme Inhibitors - chemistry / Angiotensin-Converting Enzyme Inhibitors - isolation & purification / Angiotensin-Converting Enzyme Inhibitors - pharmacology / Angiotensin-Converting Enzyme Inhibitors - therapeutic use / Antihypertensive Agents - chemistry / Antihypertensive Agents - isolation & purification / Antihypertensive Agents - pharmacology / Antihypertensive Agents - therapeutic use / Antihypertensives / Blood pressure / Carbohydrates / Chromatography / Chymotrypsin / DNA / Drug Stability / Enzyme Assays / Enzymes / Enzymolysis / Fractionation / Gels / High-performance liquid chromatography / HPLC / Hydrogen bonds / Hydrolysates / Hydrolysis / Hypertension / Hypertension - drug therapy / Inhibitory Concentration 50 / Liquid chromatography / Mass spectrometry / Mass spectroscopy / Methionine / Molecular docking / Molecular Docking Simulation / Molecular weight / Nucleotide sequence / optimization / Papain / Pepsin / Peptide Hydrolases - metabolism / Peptides / Peptides - chemistry / Peptides - isolation & purification / Peptides - pharmacology / Peptides - therapeutic use / Peptidyl-dipeptidase A / Peptidyl-Dipeptidase A - chemistry / Peptidyl-Dipeptidase A - metabolism / Protein Hydrolysates - chemistry / Protein Hydrolysates - isolation & purification / Protein Hydrolysates - metabolism / Proteins / purification / Response surface methodology / Seaweed - chemistry / Seaweeds / structural identification / Substrates / Subtilisin / Trypsin / Ultrafiltration / Ulva / Ulva intestinalis / Water purification / Zinc