Identification of an Antihypertensive Peptide from Casein Hydrolysate Produced by a Proteinase from Lactobacillus helveticus CP790

Abstract

Casein hydrolysate, produced by an extracellular proteinase from Lactobacillus helveticus CP790, was fractionated by two-step reverse-phase HPLC. Only one fraction showed antihypertensive activity as measured by systolic blood pressure in spontaneously hypertensive rats after oral administration. Ten peptides in the fraction were further purified and identified by analysis of amino acid sequences. Each identified peptide was chemically synthesized, and the antihypertensive activity of each peptide was evaluated in spontaneously hypertensive rats. The synthetic peptide with a sequence of Lys-Val-Leu-Pro-Val-Pro-Gln, found in beta-casein, indicated strong antihypertensive activity from 2 to 10 h after oral administration of 2 mg of peptide/kg of BW, and the effect 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. Interestingly, the antihypertensive peptide showed lower inhibitory activity of angiotensin I-converting enzyme, but the activity was increased after pancreatin digestion.

ACE-inhibitory activity and ACE-inhibiting peptides in different cheese varieties

“…The strains L. helveticus CP790 [57,137] and L. helveticus LBK-16 [110] have been successfully applied for the formation of VPP and IPP in two commercial fermented-milk products with antihypertensive capacity (Ameal S TM and Evolus ® ). Similarly, other L. helveticus strains such as NCC 2765 [100], PR4 [69] or 130B4 from camel milk [113] and in a further study [82] two highly proteolytic strains of L. helveticus (MI 1198, MI 1263), as well as strains of Lc.…”

Whey Proteins as Source of Bioactive Peptides Against Hypertension

“…For instance, YKVPQL identified in a casein hydrolyzate and released by a proteinase from L. helveticus CP790, had a high in vivo ACE-inhibitory activity (IC50 22 M) but did not show any antihypertensive one [282] -probably as a consequence of degradation during the digestion process [137]. When the hydrolyzate was purified, another peptide sequence (KVLPVPQ) was found.…”

“…However, some peptides with in vivo antihypertensive activity -as is the sequence KVLPVPQ, and which did not show in vitro ACE-inhibitory activity, could be transformed to active forms via gastrointestinal digestion [282]. Simulation of digestion is also useful in studies of the mechanism of action of antihypertensive peptides with demonstrated in vivo activity.…”

“…Several studies have accordingly provided evidence for this realization -as happened with Manchego cheese, as well as with other fermented solutions and infant formulae [100,261,[278][279][280][281]; for instance, a potent antihypertensive peptide was released via gastrointestinal digestion from a precursor with poor ACE-inhibitory activity in vitro [282] -and some peptides possess a remarkable intrinsic stability, whereas others are susceptible to unwanted degradation [136,261,281]; however, whether of any of those options will apply cannot be known in advance.…”

Lactic Fermentation and Bioactive Peptides

“…In some cases, pancreatic digestion is needed to produce active peptide. For instance, the active form of peptide Lys-Val-Leu-Pro-Val-Pro-Glu is generated by hydrolysis of the glutamine residue at the C-terminal during pancreatic digestion [107]. The results are not completely predictive of the resistance of the bioactive peptides because they do not mimic all the physiological factors affecting food digestion, as pH variations, the relative amounts of the enzymes, the interactions with other molecules, and the ratio peptidase/tested compound.…”