Identification of a gene involved in the synthesis of a dipeptidyl peptidase IV inhibitor in Aspergillus oryzae.

WYK-1 is a dipeptidyl peptidase IV inhibitor produced by Aspergillus oryzae strain AO-1. Because WYK-1 is an isoquinoline derivative consisting of three l-amino acids, we hypothesized that a nonribosomal peptide synthetase was involved in its biosynthesis. We identified 28 nonribosomal peptide synthetase genes in the sequenced genome of A.

Identification and characterization of a novel fermented substance produced by edible Aspergillus oryzae AO-1 that inhibits DPP-IV activity.

We identified a novel fermented substance (FKA) produced by the edible Aspergillus oryzae strain AO-1 that inhibited dipeptidyl peptidase IV (DPP-IV) (IC(50) = 3.41 mg · mL(-1)). HPLC analysis of FKA showed specific one metabolite (WYK-1), which inhibited DPP-IV (IC(50) = 6.