Isolation and Identification of an Angiotensin-I Converting Enzyme Inhibitory Peptide from Yeast (Saccharomyces cerevisiae)

Angiotensin-I converting enzyme (ACE) has an important function in blood pressure regulation. ACE-inhibitory peptides can lower blood pressure by inhibiting ACE activity. In this investigation, water-soluble proteins were extracted from yeast (Saccharomyces cerevisiae) and hydrolyzed by yeast protein extraction enzyme to isolate ACE-inhibitory peptides. Peptides with ACE-inhibitory activity were further separated and purified by ultrafiltration and fast protein liquid chromatography (FPLC). A hexapeptide, Thr-Pro-Thr-Gln-Gln-Ser, with a calculated molecular weight of 660Da, was purified and identified by MALDI-TOF-MS. The hexapeptide showed remarkable ACE-inhibitory activity, with an IC50 of 73.25 mu g/mL. The level of ACE-inhibitory activity of the hexapeptide indicated that it is a good candidate for development of a hypotension drug or functional food.