Purification and characterization of angiotensin-I-converting enzyme inhibitory peptides isolated from whey proteins of milk fermented with Lactobacillus plantarum QS670

Abstract

An angiotensin-converting enzyme inhibitory (ACEI) peptide with a median inhibitory concentration (IC 50 ) of 1.26 mg/mL was purified from whey proteins resulting from a fermentation using Lactobacillus plantarum QS670. The peptide was subsequently derived from an α S1 -casein, κ-casein, β-lactoglobulin, or serum albumin fraction. Analysis via liquid chromatography tandem mass spectrometry indicated that it had an amino acid sequence of Gly-Ala (GA). The GA dipeptide was also synthesized using an Fmoc solid-phase method. The GA dipeptide exhibited an IC 50 of 1.22 mg/mL and was shown to be stable across both temperature (20 to 60°C) and pH (2 to 12). Digestive enzymes including pepsin, trypsin, and chymotrypsin had negligible effects on activity. The whey exerted hypotensive effects when fed to spontaneously hypertensive rats (SHR), which exhibited a blood pressure drop of 2.33 kPa. A 4-wk gavage treatment resulted in greater decreases of 7.46 kPa. Results of this study indicate that milk fermented using Lb. plantarum QS306 has potential to be used as a functional food to help prevent or reduce hypertension-associated diseases.

Transport, In Vivo Antihypertensive Effect, and Pharmacokinetics of an Angiotensin-Converting Enzyme (ACE) Inhibitory Peptide LVLPGE

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Neuroprotective effects of fermented yak milk-derived peptide LYLKPR on H2O2-injured HT-22 cells

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“…If digestive enzymes, such as pepsin and chymotrypsin, can destroy these ACEI peptides, these functional foods will scarcely have any benefits. According to Yanan Xia et al [ 57 ], ACEI peptides isolated from whey proteins of milk fermented with Lb. plantarum QS670 exhibited stability toward chymotrypsin, pepsin, and trypsin, which meant that the fermented milk can be used as a potential functional food to help relieve the symptoms of hypertension.…”