Oligopeptides hydrolysed by muscle dipeptidyl peptidases can generate angiotensin-I converting enzyme inhibitory dipeptides

Dipeptidyl peptidases (DPP) are a group of enzymes capable to liberate dipeptides from the N-terminal side of longer peptides. Four different DPP activities have been described in skeletal muscle, each one of them having different biochemical characteristics. The four enzymes have proved to remain active during meat ageing and during processing of cured meat products. So, the fact that dipeptides are present at the end of the curing process could be related to the action of DPP during this period. In the present work we investigated DPP action on the hydrolysis of oligopeptides and its ability to generate dipeptides with antihypertensive properties by studying its inhibitory effect on angiotensin-I converting enzyme. Among the assayed dipeptides, Val-Tyr showed the strongest ACE inhibitory activity with an IC50 value of 4.6 mu M under our assay conditions. In a lower degree, Arg-Ser also proved to be a strong ACE inhibitor. The effect of Arg-Phe, Gly-Phe, Met-Ala and Val-Gly was lower though still remarkable. The present results stress forward the importance of DPP in the generation of antihypertensive peptides during the processing of meat products.