| Project/Area Number |
61560117
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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 |
000130000136000246
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| Research Institution | Kyoto University |
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Principal Investigator |
NAGASAWA Toru Kyoto University, Faculty of Agriculture, Assistant, 農学部, 助手 (60115904)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMIZU Sakayu Kyoto University, Faculty of Agriculture, Assistant, 農学部, 助手 (70093250)
IZUMI Yoshikazu Kyoto University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (40026555)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | -chloroalanine / O-acetylserine sulfhydrylase / -chloroalanine dehydrochlorinase / L-cysteine / D-cysteine / 半合成セファロスポリン / 【B_6】酵素 / 酵素的転換 / Bacillus sphaerincus / Pseudomonas putida |
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| Research Abstract |
Recent development of chemical synthesis techniques has made it possible to produce <beta>-chloroalanine economically on a large scale. The enzymatic transformation of chemically synthesized <beta>-chloroalanie into useful amino acids was studied. We isolated microorganisms, Bacillus sphaericus L-118 and Pseudomonas putida CR1-1 which are resistant to <beta>-chloro-L-alanine and -chloro-D-alanine, respectively. The formation of O-acetylserine sulfhydrylase of B. sphaericus L-118, was highly enhanced by (beta)-chloro-L-alanine to the medium. The enzyme catalyzes the <beta>-replacement reaction of <beta>-chloroalanine in the presence of sulfide to produce L-cysteine. We optimized the reaction conditions for the enzymatic production of L-cysteine. Under the optimum conditions. 70 g of L-cysteine/L of reaction mixture was produced (conversion yield 80%). In the crude cell extract of P. putida CR 1-1, we found the new enzyme, <beta>-chloro-D-alanine dehydrochlorinase which catalyzes the <beta>-replacement reaction of <beta>-chloro-D-alanine in the presence of sulfide to produce D-cysteine. When various thiol compounds were added instead of sulfide, the corresponding Salkyl-D-cysteine was synthesized. We optimized the reaction conditions to produce D-cysteine. Under the optimal condition, 22.6 g of D-cysteine/L of reaction mixture was produced (conversion yield 100%). D-Cysteine and its derivatives are useful for the production of the semi-synthetic cephalosporin antibiotics.
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