Prolyl Endopeptidase Inhibitors in Sake and Its Byproducts

The purification of the inhibitory peptide for prolyl endopeptidase from sake (alcohol beverage in Japan) and its byproduct was studied. Prolyl endopeptidase resolves the antidiuretic hormone vasopressin, which is also involved in the maintenance of memory. After confirming the inhibitory activities in pepsin hydrolysate of sake cake (byproduct of sake) and sake concentrate, we separated them with several chromatographic procedures. Three inhibitory peptides were obtained from sake cake, and another three inhibitory peptides were obtained from sake. These peptides inhibit prolyl endopeptidase in vitro . These sequences exist in rice glutelin.