Purification and identification of antioxidant and ACE-inhibitory peptide from Saccharomyces cerevisiae protein hydrolysate

Yeast protein hydrolysate may be considered as a good source of bioactive peptides. Yeast hydrolysate was prepared by two different physical-enzymatic and autolysis treatments to identify the most active angiotensin I-converting enzyme (ACE) inhibitory and antioxidant peptides. The most active hydrolysate was obtained after sonication-trypsin hydrolysis. The hydrolysate was subjected to fractionation by ultrafiltration. Fraction with molecular weight of <3 kDa exhibited the highest activity. Reverse phase high performance liquid chromatography (RP-HPLC) resolved this fraction into five fractions, one of which (fraction F3) with amino acid sequence of Try-Gly-Lys-Pro-Val-Ala-Val-Pro-Ala-Arg (MW:1057.45 Da) exhibited ACE inhibitory (IC50 = 0.42 +/- 0.02 mg/ml) and antioxidant activities (26.25 +/- 0.13 mu M TE/mu g protein). Taken together, the results of this study show that S. cerevisiae proteins contain specific peptides in their sequences which can be released by enzymatic hydrolysis. These peptides have excellent bioactive properties that can potentially replace the antioxidant and antihypertensive agents with chemical origin. (C) 2015 Elsevier Ltd. All rights reserved.