Characterization of newly found intracellular metallo-carboxypeptidases by genome sequencing of A. oryzae

Youhei Yamagata[1] Hiroshi Maeda[1] Ken-ichi Kusumoto[2] Yoshinao Koide[3] Hiroki Ishida[4] Michio Takeuchi[1]

Author address: 

1Dep. of Agriscience & Bioscience. Tokyo University of Agriculture & Technology, Tokyo, Japan 2NFRI, Ibaraki, Japan, 3Amano Enzyme Inc., Gifu, Japan, 4Gekkeikan Sake Company Ltd., Kyoto, Japan


Aspergillus oryzae is one of industrial microorganism as using for the Japanese traditional fermented food. The genome project of A. oryzae clarified that there were 134 genes coding proteolytic enzymes. We have been trying to characterize all proteolytic enzymes. We found that A. oryzae had twelve genes for metallo-carboxypeptidases. Nine of them do not have the signal peptide, and it is presumed that these enzymes would be localized intracellularly. The enzymes were all classified in M20 super-family. As four of the enzyme genes were translated under the liquid culture condition, the genes were cloned and expressed in E. coli. The two purified enzymes (AOEXE305 and AOEXE306) showed maximum activity at alkaline pH in spite of those are intracellular enzymes. It was shown that acidic amino acid was favorable in P1’ site for AOEXE305. AOEXE306 showed wider substrate specificity than AOEXE305. The enzyme could cleavage between even Xaa-Pro bonds but did not favor acidic amino aicd in S1’ in substarates. The results might indicate that fungal intracellular metallo-carboxypeptidases had different roll in fungal cells. This study was supported by the Program for Promotion of Basic Research Activities for Innovative Biosciences (PROBRAIN).

abstract No: 


Full conference title: 

    • ECFG 10th (2010)