Antihypertensive Peptides Derived from Soy Protein by Fermentation.

Soy protein is widely used as a nitrogen source
in infant and adult formulations, both in an intact and
hydrolyzed form. Here, the objective was to screen for
maximum proteolytic activity in different strains of lactobacillus
and use it for fermentation of soy protein to obtain
Angiotensin converting-I-enzyme (ACE I) inhibitory peptides
for its use as a nutraceutical. Based on the proteolytic
activity, Lactobacillus casei spp. pseudoplantarum was
selected. The two ACE inhibitory peptide fractions F2 and
F3 were isolated having IC50 values of 17 ± 0.63 and
30 ± 0.13 lg/ml respectively. The N-terminal sequence of
peptide (F2) was determined to be Leu-Ile-Val-Thr-Gln
(LIVTQ). The peptide analogues of LIVTQ were synthesized
to study the effect of individual residues on ACE
enzyme. LIVTQ and LIVT peptides show inhibition
against ACE enzyme having an IC50 value of 0.087 and
0.110 lM respectively. Our results depict that glutamine
(Q) and threonine (T) residues have an important role in
ACE inhibition.