The antihypertensive
effect of rice protein hydrolysate was also investigated in spontaneously hypertensive rats (SHR). The Alcalase-
generated hydrolysate showed strong in vitro ACE inhibitory activity with the IC50 value of 0.14 mg/ml. A significant
decrease in systolic blood pressure in spontaneously hypertensive rats was observed following single oral
administration of this hydrolysate at a dose of 600 mg/kg of body weight. A potent ACE inhibitory peptide with the
amino acid sequence of Thr-Gln-Val-Tyr (IC50, 18.2 μM) was isolated and identified from the hydrolysate. Single
oral administration of Thr-Gln-Val-Tyr at a dose of 30 mg/kg of body weight also significantly decreased blood pressure
in SHR.