2005 Fiscal Year Final Research Report Summary
Structure and Electron Transfer of Quinoproteins and application to Bio-electrode Devices
| Project/Area Number |
15380082
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bioproduction chemistry/Bioorganic chemistry
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| Research Institution | Kyoto University |
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Principal Investigator |
KANO Kenji Kyoto Univ., Grad.Sch.Agric., Prof., 農学研究科, 教授 (10152828)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Histamine dehydrogenase / 6-S-cyteinyl-FMN / Expression system / Quinohemoproteins / Amine dehydrogenase / Alcohol dehydrogenase / Biosensors / Biofuel cells |
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| Research Abstract |
1)Structural analysis and Electron Transfer Characteristics of Histamine Dehydrogenase (HmDH)
It has been revealed that HmDH has 6-S-cyteinyl-FMN and 4Fe-4S cluster as redox prosthetic groups. Under neutral conditions, 2-electron reductions occurs per monomer by the substrate, while the number of the electron is switched to unit over pH 9.5. The properties can be explained in terms of the change in the redox potentials. The kinetics of half-reduction has been analyzed with stopped flow method. The holo form of HmDH has been expressed in E.coli in the purity of 100%. Site-directed mutation improve the specificity of the enzyme.
2)Electron Transfer of Quinohemoproteins
Positive charge in the vicinity of the active site of quinohemoprotein amine dehydrogenase (QH-AmDH) plays an important role in the electron transfer from to electron acceptor. The direct electron transfer from QH-AmDH to electrodes was not observed. The redox potentials of quinohemoproteins alcohol dehydrogenase depend on pH. This would be due to the structural change of the enzyme.
3)Application to Biosensor and Biofuel Cells
It has been found that mutant HmDH works as a good catalysis of mediated biosensor for histamine with high specificity. Selectivity of mediator reduced the interference. The dehydrogenases invested here were utilized also as catalysts in bioanode of biofuel cells, where bilirubin oxidase (BOD) was used as cathode enzyme. Direct electron transfer of BOD is affected by the electrode materials. The current density were increased up few ten mA cm^<-2>.
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