LAUSR

BACKGROUND We synthesised a novel sericin peptide (SP-GI) with α-d-glucosidase inhibitory activity, which has a sequence of SEDSSEVDIDLGN. The kinetics of its peptide-induced inhibition on α-d-glucosidase activity and its interaction mechanism merging with molecular docking were both investigated. RESULTS SP-GI exhibited significant inhibitory activity with an IC50 of 2.9 ± 0.1 µmol L-1 and this inhibition was reversible and non-competitive with a Ki value of 1.0 ± 0.1 µmol L-1 . An interaction study with SP-GI revealed it bound to α-d-glucosidase at a single binding site, resulting in alterations in α-d-glucosidase secondary structure. This led to quenching of intrinsic α-d-glucosidase fluorescence by a static quenching mechanism. Molecular docking results showed that the SP-GI binding site on α-d-glucosidase differed from acarbose, with hydrogen bonding and van der Waals forces being the main binding drivers. CONCLUSION These findings suggest the potential use for SP-GI or other natural sericin peptides as dietary supplements for the treatment of type 2 diabetes. © 2017 Society of Chemical Industry.