Evaluation and Identification of Potent Angiotensin‐I Converting Enzyme Inhibitory Peptide Derived from Dwarf Gulper Shark (Centrophorus atromarginatus)

Dwarf gulper shark (Centrophorus atromarginatus) lives in tropical to temperate waters and has a plenty of squalene in the liver. On the other hand, its muscle is an unused resource in Japan because of high urea content. Here, we tried to find the new procedure for the preparation of angiotensin-I converting enzyme (ACE) inhibitory hydrolysate from this shark. Nine hydrolysates were prepared using food-processing proteases. Among them, three hydrolysates produced by Protease P, Papain and Thermoase showed the potent ACE inhibitory activity (The IC50 values: 172.2, 144.2 and 84.2g/mL, respectively). From Thermoase hydrolysate, Val-Trp was found as the most potent inhibitory peptide (IC50 value: 3.3g/mL). The mechanism of inhibition of Val-Trp for ACE was competitive. Val-Trp also exhibited antioxidant activities, suggesting the efficacy as bifunctional peptide against hypertension. This study showed the new possibility of the usage of dwarf gulper shark as material for healthy food. Practical ApplicationsThis study introduces processing techniques for potent ACE inhibitory hydrolysate from dwarf gulper shark muscle by using food-processing proteases. This hydrolysate shows low bitterness, which is suitable for the usage as functional food. The strongest ACE inhibitory peptide in this hydrolysate also possessed antioxidant activity, suggesting that the hydrolysate would be useful for hypertension acting as bifunctional (ACE inhibitory and antioxidative). Results of this study will contribute to utilize dwarf gulper shark muscle, a nonutilized resource in Japan.