Isolation and characterization of angiotensin I-converting enzyme (ACE-I) inhibition and antioxidant peptide from by-catch shrimp (Oratosquilla woodmasoni) waste

The aim was to drive the ACE-I inhibitory peptide from the dumped waste of O. woodmasoni muscle protein hydrolysate after 12 h of hydrolysis using thermolysin and pepsin. The degree of hydrolysis (DH) was observed till 12th hr and the maximum ACE-I inhibition activity was recorded in 2nd and 5th hr (73.51 ± 0.25% & 68.93 ± 0.23%) for thermolysin and pepsin respectively. Further, the higher active thermolysin hydrolysate was separated using ultrafiltration membrane unit and 10-3 kDa fraction showed chief ACE-I inhibition activity (IC50 value: 0.47 mg/mL). The active fraction was purified by consecutive chromatographic techniques using ion exchange chromatography (IEC) & gel filtration chromatography (GFC) using fast protein liquid chromatography (FPLC). Finally, the fraction TH1-A1 evaluated by ACE-I inhibition assay and showed 77.09 ± 2.18% inhibitions. The non-toxic peptide against MCF-7 cells was further characterized for functional properties at pH 2 to 10. The active purified fraction also exhibited antioxidant activity analyzed with various assays and found to have 5 amino acid sequence (Asn-Gly-Val-Ala-Ala) with molecular weight 431 Da through LC-MS/MS. In conclusion, the identified low molecular weight peptide from by catch O. woodmasoni waste has both ACE-I inhibition and antioxidant properties. Therefore, this peptide might be a better alternative nutraceutical and functional food after few more investigations.