Microbial Cyclic Imide Metabolism and Its Biotechnological Application
Jun Ogawa1,4, Soong Chee-Leong1, Nobuyuki Horinouchi1, Masutoshi Nojiri2, Michihki Takeuchi3, Makoto Hibi3,5
Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
The microbial transformation of cyclic imides was investigated. Blastobacter sp. A17p-4 was used as a model strain for metabolism, enzyme, and physiology analysis based on its diversity of cyclic amide metabolism, including cyclic imides and cyclic ureides. Imidase and half-amidase, which are the key enzymes in this transformation, from Blastobacter sp. A17p-4 have been studied together with cyclic ureide transforming enzymes, that is, d-hydantoinase, N-carbamoyl-d-amino acid amidohydrolase, useful for d-amino acid production from dl-5-monosubstituted hydantoin. d-Hydantoinase functions in the metabolism of bulky cyclic imides, while imidase functions in that of simple cyclic imides in combination with half-amidase, which functions in the hydrolysis of the imidase reaction products, half-amides. Imidase and half-amidase are different from reported cyclic amide–metabolizing enzymes, and are widely found in bacteria, yeasts, and molds. The cyclic imide metabolism and the enzymes involved were applied for the production of useful organic acid, such as pyruvate and fine synthesis of optically active α-mercapto acids and half-amides useful as pharmaceutical intermediates.
Keywords: Cyclic imide, half-amide, imidase, half-amidase.