M. Maeno et al., IDENTIFICATION OF AN ANTIHYPERTENSIVE PEPTIDE FROM CASEIN HYDROLYSATEPRODUCED BY A PROTEINASE FROM LACTOBACILLUS-HELVETICUS CP790, Journal of dairy science, 79(8), 1996, pp. 1316-1321
Casein hydrolysate, produced by an extracellular proteinase from Lacto
bacillus helveticus CP790, was fractionated by two-step reverse-phase
HPLC. Only one fraction showed antihypertensive activity as measured b
y systolic blood pressure in spontaneously hypertensive rats after ora
l administration. Ten peptides in the fraction were further purified a
nd identified by analysis of amino acid sequences. Each identified pep
tide was chemically synthesized, and the antihypertensive activity of
each peptide was evaluated in spontaneously hypertensive rats. The syn
thetic peptide with a sequence of Lys-Val-Leu-Pro-Val-Pro-Gln, found i
n beta-casein, indicated strong antihypertensive activity from 2 to 10
h after oral administration of 2 mg of peptide/kg of BW, and the effe
ct was maximal at 6 h after oral administration (-31.5 +/- 5.6 mm Hg).
Moreover, the antihypertensive effect of the peptide was dependent on
the dosage of peptide from 0.5 to 2 mg of peptide/kg of BW. Interesti
ngly, the antihypertensive peptide showed lower inhibitory activity of
angiotensin I-converting enzyme, but the activity was increased after
pancreatin digestion.