IDENTIFICATION OF AN ANTIHYPERTENSIVE PEPTIDE FROM CASEIN HYDROLYSATEPRODUCED BY A PROTEINASE FROM LACTOBACILLUS-HELVETICUS CP790

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.