In vitro and in silico analyses of the angiotensin-I converting enzyme inhibitory activity of peptides identified from Bellamya bengalensis protein hydrolysates

The study focuses on identification of ACE-inhibitory peptides from the proteolytic digests of muscle protein of Bellamya bengalensis and its underlying mechanism. 120 min Alcalase-hydrolysates were ultrafiltered to isolate the small peptide fraction (<3kDa) and in vitro ACE-inhibitory activity was analyzed. The IC50 value of the 120 min hydrolysate ultafiltered fraction was found to be 86.74 {+/-} 0.575 {micro}g/mL, while the IC50 of Lisinopril is 0.31 {+/-} 0.07 {micro}g/mL. This fraction was assessed in MALDI-ToF mass-spectrometer and five peptides were sequenced via de novo sequencing. The ACE-inhibitory potential of the peptides have a positive correlation with the hydrophobicity of the amino acids. Synthetic analogue of the peptide (IC50 value 8.52 {+/-} 0.779 {micro}g/mL) was used to understand the thermodynamics of the inhibition by checking the binding affinity of the peptide to ACE by Isothermal titration calorimetry compared with lisinopril, and further substantiated by in silico site specific molecular docking study.