1988 Fiscal Year Final Research Report Summary
Studies on the enzymatic production of nucleosides in the activated methyl cycle
| Project/Area Number |
62470123
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
発酵・醸造
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| Research Institution | Kyoto University |
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Principal Investigator |
YAMADA Hideaki Kyoto University, 農学部, 教授 (30027180)
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| Co-Investigator(Kenkyū-buntansha) |
NAGASAWA Toru Kyoto University, 農学部, 助手 (60115904)
SHIMIZU Sakayu Kyoto University, 農学部, 助手 (70093250)
IZUMI Yoshikazu Kyoto University, 農学部, 助教授 (40026555)
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| Project Period (FY) |
1987 – 1988
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| Keywords | A. faecalis / Pseudomonas putida / L-homocysteine / D-homocysteine / アデノシルメチオニン合成酵素 / ホモシステインラセマーゼ / Pseudomonas putida |
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| Research Abstract |
We have developed a simple and efficient method for the production of AdoHcy and related nucleosides from L-homocysteine and corresponding nucleosides with A. faecalis cells as catalysts.
However, the involvement of an enzyme activity that can catalyze the interconversion of the D- and L-homocysteine isomers in the reaction system with A. faecalis cells seems very promising as a means of solving this problem. Based on this idea, we again screened microorganisms capable of utilizing both the D- and L-homocysteine isomers as substrater. As a result of this screening, Pseudomonas putida IFO 12996 and several other bacterial strains were found to act as catalysts for the conversion of adenosine and D-homocysteine to the L-form of Adohcy. For practical purposes,though, A. faecalis cells were still superior to P. putida cells because they showed high AdoHcy hydrolase activity and low adenosine deaminase activity. Therefore, we used P. putida cells only as a source of the racemase. By mixing adenosine and D,L-homocysteine with a mixture of A. faecalis cells and P. putida cells in potassium phosphate butter, we essentially obtained a 100% yield.
In a similar manner, several novel S-nucleosidylhomocysteines could be synthesized efficiently from the corresponding adenosine analogues and L-homocysteine. The K-carrageean entrapped cells of A. faecalis showed high stability on repeated reactions, whereas free cells were inactivated rapidly. These novel S-nucleosidylhomocysteines alsocould be promising for application in the pharmaceutical and chemotherapeutic fields.
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