Identification of two novel α-amylase inhibitory activity peptide from Russian sea cucumber body wallprotein hydrolysate

This study aimed to identify novel α-amylase inhibitory peptides from Russian sea cucumbers and elucidate their inhibitory mechanisms. Among the 52 identified sea cucumber peptide (SCP), two peptides with potential α-amylase inhibitory activity, FPSPPLVA (SCP1) and GPPMPPPPLP (SCP2), were selected from the sequences researched. The results showed that both SCP1 and SCP2 exhibited α-amylase inhibitory activity with IC₅₀ of 0.92 ± 0.03 mg/mL (SCP1) and 2.01 ± 0.02 mg/mL (SCP2), respectively. Molecular docking studies revealed the potential interaction mechanism between these inhibitors and α-amylase. Two peptides interacted with Gln63, Tyr151, Thr163, Lys200, His201, His305, and Ala307 within the α-amylase active site. The formation of hydrogen bonds and hydrophobic interactions between the inhibitors and α-amylase impedes the formation of enzyme-substrate complexes and subsequent glycosylation. Lineweaver-Burk plot indicated that both SCP1 and SCP2 act as reversible mixed inhibitors of α-amylase. Furthermore, the results of infrared and circular dichroism spectroscopy confirmed the formation of non-covalent binding complexes between SCP and amylase, leading to alterations in the secondary structure of the enzyme.