Purification and identification of novel angiotensin-I-converting enzyme inhibitory peptides from shark meat hydrolysate

Proteins, especially the proteins of marine origin, are potential resources of natural drugs and food additives. Our previous results showed that shark meat hydrolysate obtained with protease SM98011 digestion showed high angiotensin-I-converting enzyme (ACE) inhibitory activity, with an IC50 value of 0.4 mg/mL. In this article, ACE inhibitory peptides were separated from shark meat hydrolysate and identified. By ultrafiltration, gel filtration and RP-HPLC, 4 peptides with high ACE inhibitory activity were purified. Their sequences identified by Secondary Ion Mass Spectrometry were Cys-Phe, Glu-Tyr, Met-Phe and Phe-Glu. Cys-Phe, Glu-Tyr and Phe-Glu were conformed to be novel ACE inhibitory peptides, with IC50 values of 1.96, 2.68 and 1.45 μM, respectively. They may have potential in the treatment of hypertension or in clinical nutrition. This is the first report about novel ACE inhibitory peptides from hydrolysate of shark meat. This research may provide an efficient utilization of shark meat.