1993 Fiscal Year Final Research Report Summary
The Superoxide-generating system and its bactericidal reaction of leukocytes.
| Project/Area Number |
04670265
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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 |
細菌学
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| Research Institution | The Tokyo Metropolitan Institute of Medical Science |
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Principal Investigator |
MIKI Toshiaki The Tokyo Metropolitan Institute of Medical Science, Department of Imflammation Research, Research Scientist, 炎症研究部門, 研究員 (10239204)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Lucia S. The Tokyo Metropolitan Institute of Medical Science, Department of Imflammation, 炎症研究部門, 研究員 (20240327)
FUJII Hirotada The Tokyo Metropolitan Institute of Medical Science, Department of Imflammation, 炎症研究部門, 研究員 (70209013)
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| Project Period (FY) |
1992 – 1993
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| Keywords | leukocyte / neutrophil / superoxide / active oxygens / NADPH oxidase / cytochrome b-558 / chronic granulomatous disease / electron spin resonance |
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| Research Abstract |
The generation of O_<2^^-> in granulocytes, such as neutrophils and eosinophils, is catalyzed by a membrane-associated electron transport enzyme system named NADPH oxidase. Cytochrome b-558, one essential member of the NADPH oxidase, is characterized by ESR spectrometry to elucidate its heme environment. Ueno et al. have reported that cytochrome b-558 in a thick granulocyte suspension shows low spin heme signals at g values of 2.85, 2.21, and 1.67 (FEBS Lett.281 : 130-132, 1991). However, our present studies on pig blood granulocytes suggest that these low spin signals may be due to a low spin form of eosinophil peroxidase, and that cytochrome b-558 shows a low spin signal at a g value of around 3.2 at both cellular and subcellular levels. The g value is further confirmed by measuring ESR spectra of cytochrome b-558 purified from granulocyte membranes. The purified cytochrome b-558 containing its two subunits exhibits the ability to reconstitute O_<2^^-> generating NADPH oxidase activity in an in vitro cell-free assay system. The purified and undenatured cytochrome b-558 shows an ESR signal at a g value of 3.26 at 10 K.The low spin signal at g=3.26 is not affected by addition of 2 mMKCN, but disappears completely on reduction with Na_2S_2O_4. These results suggest that g=3.26 signal is characteristic of the low spin heme in cytochrome b-558 of granulocytes.
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