Purification, identification, and characterization of novel angiotensin I-converting enzyme (ACE) inhibitory peptides from alcalase digested horse gram flour

Abstract

Abstract The present study identified at least two novel angiotensin I-converting enzyme (ACE) inhibitory peptides in horse gram flour after hydrolysis with alcalase. The ACE inhibitory peptides from horse gram hydrolysate (HGH) were purified by ultrafiltration and different chromatography techniques followed by identification using nano liquid chromatography-mass spectrometry (nano LC-MS/MS). Further, based on in silico analysis, twelve potential ACE inhibitory peptides from HGH were synthesized and assayed for their ACE inhibitory activity. Two peptides TVGMTAKF and QLLLQQ exhibited the highest ACE inhibitory activity (IC50 values of 30.3\u202fμM and 75.0\u202fμM, respectively) and were characterized kinetically to show Ki values of 0.01\u202fμM and 0.18\u202fμM, respectively. In addition, these two novel peptides exhibited competitive mode of inhibition as well as retained their ACE inhibitory activity after incubation with gastrointestinal proteases (pepsin, trypsin, and chymotrypsin). Thus, the ACE inhibitory peptides identified from HGH shows promise to be used as a functional food ingredient for controlling hypertension.