| Project/Area Number |
60560113
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 |
SODA Kenji Institute for Chemical Research, Kyoto University, 化学研究所, 教授 (30027023)
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| Co-Investigator(Kenkyū-buntansha) |
HIRASAWA Toshiko Institute for Chemical Research, Kyoto University, 化学研究所, 教務職員 (80238352)
ESAKI Nobuyoshi Institute for Chemical Research, Kyoto University, 化学研究所, 助手 (50135597)
TANIZAWA Katsuyuki Institute for Chemical Research, Kyoto University, 化学研究所, 助手 (20133134)
TANAKA Hidehiko Institute for Chemical Research, Kyoto University, 化学研究所, 助教授 (90065912)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1985: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Selenium-containing amino acids / tellurium-containing amino acids / enzymatic synthesis / pyridoxal enzymes / L-methionine <gamma> -lyase / O-acetylhomoserine(thiol)-lyase / tryptophan synthase / 置換反応 |
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| Research Abstract |
Various selenium-containing amino acids occur in nature, and most of them are physiologically active. The present study has been undertaken to prepare optically active selenium-containing amino acids, which are synthesized chemically with great difficulty, with multi-functional pyridoxal-P enzymes, and also to clarify the mechanism of the enzymatic reactions. The results that we have obtained are as follows.
(1) We have synthesized tellurium-containing amino acids, which are expected to be useful as a specific imaging agent for pancreas. Te-Phenyl-L-tellurohomocysteine and Te-phenyl-L-tellurocysteine have been synthesized.
(2) Various optically-active selenium-containing amino acids have been obtained from selenols and cheaply-available amino acids with bacterial L-methionine <gamma> -lyase and yeast O-acetylhomoserine(thiol)-lyase. As both the enzymes catalyze not only <beta> but also <gamma> -replacement reactions, we could synthesize not only Se-substituted-L-selenocysteine but Se-substituted-L-selenohomocysteine. O-Acetylhomoserine(thiol)-lyase catalyzes only replacement reactions. Therefore, the synthetic reactions proceed efficiently in contrast with that with L-methionine <gamma> -lyase which catalyzes elimination reactions in addition to replacement reactions.
(3) However, we have found that L-methionine <gamma> -lyase entrapped in polyurethane catalyzes only replacement reactions, and that the modified enzyme works actually as an efficient biocatalyst for the synthesis of selenium amino acids.
(4) We have also developed a novel synthetic procedure for optically-active selenium-containing amino acids with bacterial tryptophan synthase, which inherently functions in the tryptophan synthesis.
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