抄録
Miso paste is produced with koji molds, which are industrial strains of Aspergillus oryzae. They produce high level of enzymes and do not produce toxic metabolite. In these reasons these molds are used in manufacturing fermented food. The studies on koji molds-derived enzymes proceed with genome analysis and post-genome analysis using genome information. From these studies, several novel peptidases were identified, which revealed activity to release amino-terminal amino acids from peptides. For instance, DapA released only glutamate and aspartate. PapA released only proline （and hydroxyproline）. LapA released leucine and other hydrophobic amino acids. These aminopeptidases were produced in high level by genetic engineering of A. oryzae, and then were purified from cell-free extract after cell disruption, except LapA, which was purified from the culture media as it is extracellular enzyme. Cysteinyl dipeptidase CdpA and lysyl aminopeptidases ApsA and B were produced intracellularly with Escherichia coli. GdaA released glycine and d-alanine. DamA released d-leucine and d-phenylalanine. These peptidases were categorized as d-aminopeptidase. Some of the intracellular peptidases （DapA and GdaA） were leaked from the mycelia when koji molds were grown as solid culture ‘koji’. Another topic is the regulation of phosphatase which hydrolyzes umami-enhancing ribonucleotides in the process of dashi-added miso.
