Antihypertensive effect of angiotensin-converting enzyme inhibitory peptide obtained from hen ovotransferrin

Angiotensin I-converting enzyme (ACE) inhibitory peptide was isolated from the hen ovotransferrin hydrolysate using chymotryptic hydrolysis by two steps of reverse-phase high-performance liquid chromatography. The amino sequence of this novel peptide was identified as Lys-Val-Arg-Glu-Gly-Thr-Thr-Tyr that inhibited ACE activity in vitro in a concentration-dependent manner with an effective concentration (IC50) of 102.8 mu M. Also, this inhibition was identified as noncompetitive using the Lineweaver-Burk plot. Moreover, the antihypertensive action of this novel peptide was investigated by an intravenous injection into spontaneously hypertensive rats (SHR). A dose-dependent reduction of systolic blood pressure by this peptide was observed after 40 min of treatment and it decreased the blood pressure markedly at the maximal dose (1 nmol/mL/kg). The maximal blood pressure lowering activity of this peptide was calculated as 163% of captopril (10 pmol/mL/kg) that was used as positive control. In conclusion, the obtained data suggests that Lys-Val-Arg-Glu-Gly-Thr-Thr-Tyr has an ability to inhibit ACE activity and decrease the systolic blood pressure in hypertensive animals.