A novel antioxidant and ACE inhibitory peptide from rice bran protein: Biochemical characterization and molecular docking study

Rice bran protein was hydrolyzed using trypsin. The hydrolysate (RBPH) was then further separated by membrane bioreactor system, gel filtration and reversed phase high-performance liquid chromatography (RP-HPLC). A novel antioxidant and angiotensin I-converting enzyme (ACE) inhibitory peptide named as F2-a, which exhibited high DPPH center dot free radicals scavenging activity, reducing power and ACE inhibitory activity (IC50 of 76 mu M) was isolated. The amino acid sequence, Tyr-Ser-Lys (Mw: 395.0 Da), was identified by Quardrupole Time-of-flight Mass Spectrometer (Q-TOF-MS) with an electro-spray ionization (ESI) source. The molecular docking study revealed that the ACE inhibition of Tyr-Ser-Lys was mainly attributed to forming very strong hydrogen bonds with the active pockets of human ACE. These results indicate that rice bran is a potential source of bioactive peptides possessing antioxidant and ACE inhibitory activities. (C) 2016 Elsevier Ltd. All rights reserved.