Studies on Cytochrome P-450 of the fungus, Fusarium oxysporum

尖镰孢细胞色素P-450的研究

• 批准号: 62560096
• 负责人: SHOUN Hirofumi
• 金额: $ 1.22万
• 依托单位: University of Tsukuba
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-62560096/
• 关键词: cytochrome P-450; nitrate; nitrite-inducible; Fusarium; denitrification; モノオキシゲナーゼ; 硝酸誘導型; 亜硝酸還元

(1) A semianaerobic culture of the cytochrome P-450(P-450)-producing fungus, Fusarium oxsporum, was shown to evolve nitrogen gas(N_2) then nitrite(or nitrate) was present in the culture medium. This process(denitrification) is now under investigation whether it is due to biological or non-biological reactions.(2) In addition to P-450 cytochrome b_5 was isolated from F. oxysporum. It was shown that the fungus possesses an electron transport system similar to those in hepatic microsomes.(3) The mechanism of induction of P-450 by nitrate(nitrite) was further studied. Addition of nitrate by the concentration as low as below l mM was sufficiently effective in inducing P-450 in the fungus. Other nitrogen sources such as ammonium or amino acids or sulfate were not effective. P-450 was induced on 1-2 days after addition of nitrate. The induction was not repressed by ammonium or other reduced nitrogen souces showing that the P-450 is not involved in the assimilatory metabolism of nitrate. On the other hand, the induction was inhibited by cycloheximide.(4) Distribution of the nitrate-inducible P-450 among eukaryotic microorganisms was investigated. It was shown to be restricted to several species of Fusarium and Gibberella Fujikuroi. The cell-free extracts of these fungi contained intrate-inducible P-450 as well as substances that cross-react with the antibody against purified nitrate-inducible P-450.

(1)产生细胞色素P-450(P-450)的真菌Fusarium oxsporum的半厌氧培养物显示出放出氮气(N_2)并且培养基中存在亚硝酸盐(或硝酸盐)。目前正在研究这一过程（反硝化）是否是由于生物反应或非生物反应引起的。(2)除了P-450之外，还从尖孢镰刀菌中分离出细胞色素b_5。结果表明，该真菌具有与肝微粒体相似的电子传递系统。(3)进一步研究了硝酸盐(亚硝酸盐)诱导P-450的机制。添加浓度低至低于1mM的硝酸盐足以有效地诱导真菌中的P-450。其他氮源如铵、氨基酸或硫酸盐均无效。添加硝酸盐后1-2天诱导P-450。该诱导不受铵或其他还原氮源的抑制，表明 P-450 不参与硝酸盐的同化代谢。另一方面，放线菌酮的诱导受到抑制。(4)研究了硝酸盐诱导型P-450在真核微生物中的分布。它被证明仅限于几种镰刀菌和藤黑赤霉。这些真菌的无细胞提取物含有内部诱导型 P-450 以及与纯化的硝酸盐诱导型 P-450 抗体发生交叉反应的物质。

项目成果

祥雲 弘文: Journal of Biochemistry.

Hirofumi Shoun：生物化学杂志。

祥雲弘文: FEBS LETTERS. 244. 11-14 (1989)

庄野博文：FEBS 信件 244. 11-14 (1989)

祥雲弘文: FEBS LETTERS. 244. 11-14 (1989)

庄野博文：FEBS 信件 244. 11-14 (1989)

祥雲弘文: FEMS Microbiology Letters.

Hirofumi Shogumo：FEMS 微生物学快报。

祥雲 弘文: Agricultural and Biological Chemistry.

Hirofumi Shoun：农业和生物化学。