Characterization of secretase inhibitory peptide purified from skate skin protein hydrolysate

The objective of this study was to purify and characterize the secretase inhibitor from enzymatic hydrolysates of skate skin, for the development of a novel antidementia agent that may be utilized in the drug or functional food industries. secretase inhibitory peptide was purified from various enzymatic hydrolysates of skate skin. Among six enzymatic hydrolysates, the Neutrase hydrolysate showed the highest secretase inhibitory activity. Consecutive purification of the skate skin hydrolysate using Sephadex G-25 column chromatography and octadecylsilane C^sub 18^ reversed phase HPLC techniques was used to isolate a potent secretase inhibitory peptide composed of 12 amino acids, Gln-Gly-Try-Arg-Pro-Leu-Arg-Gly-Pro-Glu-Phe-Leu (MW: 1,391 Da). The purified peptide had strong secretase inhibitory activity, with IC^sub 50^ value of 24.26 [mu]M, and displayed a non-competitive mode of inhibition. Among the synthesized [beta]-secretase inhibitory peptides, the tetrapeptide Pro-Glu-Phe-Leu had the highest secretase inhibitory activity. The result of this study suggests that the secretase inhibitory peptide derived from skate skin could be potential candidates to develop nutraceuticals and pharmaceuticals. [PUBLICATION ABSTRACT]