Purification and identification of an ACE inhibitory peptide from the peptic hydrolysate of Acetes chinensis and its antihypertensive effects in spontaneously hypertensive rats

P>Acetes chinensis is a marine shrimp found in the coastal waters of China. The shrimp was hydrolysed by pepsin to prepare hydrolysates with angiotensin I-converting enzyme (ACE) inhibitory activity. The hydrolysate with the highest ACE inhibitory activity resulted from a 3-5 h incubation at 45 degrees C and pH 2.5 with pepsin. Gel filtration and RP-HPLC were used to separate ACE inhibitory peptides from the hydrolysate. The gel filtration fraction of the hydrolysate with a molecular weight range from 1320 Da to 311 Da exerted the highest ACE inhibition activity. This fraction was separated by RP-HPLC into fifteen fractions, of which fraction F9 showed 92.7% of the ACE inhibition activity. Its peptide sequence was determined to be Leu-His-Pro. It showed a potent antihypertensive activity in spontaneously hypertensive rats. The results suggested that this peptide may be a potent ACE inhibitor which might be developed into a healthy food to lower blood pressure.