| Project/Area Number |
05806010
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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 |
応用微生物学・応用生物化学
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
KATAYAMA Yoko Tokyo Univ. of Agric. and Technol., Fac. of Agric., Associate Prof., 農学部, 助教授 (90165415)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1994: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1993: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Sulfur Bacterium / Thiobacillus thioparus / Metabolism of Sulfur Compound / Carbonyl Sulfide / Thiocyanate Hydrolase / Microbial Treatment of Thiocyanate / Regulation of Enzyme Activity / 酵素誘導 / 酵素阻害 |
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| Research Abstract |
Changes of the enzyme level of thiocyanate hydrolase in Thiobacillus thioparus cells and inhibitory reaction of various chemicals to thiocyanate hydrolase were investigated to characterize thiocyanate degrading activity of the bacteria. Thiocyanate degradation by this bacterium was strongly inhibited by the presence of thiosulfate that is a good substrate for autotrophic energy source for this bacterium. Addition of thiosulfate in culture medium containing thiocyanate decreased cellular level of thiocyanate hydrolase in vivo, which were estimated by using antibodies against subunit proteins of thiocyanate hydrolase. Incorporation of [^<14>C] Leu following immunoprecipitation of the enzyme protein was suppressed by the addition of thiosulfate. These results suggested that thiosulfate inhibited de novo synthesis of thiocyanate hydrolase proteins. Further experiment on gene cloning and molecular analysis of the gene is useful to understand inhibitory effect of thiosulfate on the protein systhesis of thiocyanate hydrolase.
Cyanide strongly inhibited the activity of thiocyanate bydrolase, Which inhibition was noncompetitive to thiocyanate and was restored by a gel filtration. Carbonyl reagents, such as hydroxylamine, borohydride, and TNBC that is a structural analog for thiocyanate and cyanide, also inhibited the enzyme activity. These compounds seemed to react with a site different from the active center of the thiocyanate hydrolase. Furthermore reaction site of borohydride with the enzyme was different from those of cyanide and TNBC.Both cyanide and TNBC inhibited the enzyme activity at quite low concentration, and they have analogous structure to the enzyme substrate, therefore these compounds are thouht to react with a specific site that has an important function to manifest the enzyme activity, locating at close to the active center of the enzyme protein.
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