2007 Fiscal Year Final Research Report Summary
Preparation of Heme-Protein Based Birtatslysts with High Enzymatic Activity
| Project/Area Number |
17350085
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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 |
Chemistry related to living body
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| Research Institution | Osaka University |
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Principal Investigator |
HAYASHI Takashi Osaka University, Graduate School of Engineering, Professor (20222226)
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| Co-Investigator(Kenkyū-buntansha) |
HISAEDA Yoshio Kyushu University, Faculty of Engineering, Professor (70150498)
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| Project Period (FY) |
2005 – 2007
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| Keywords | hemoprotein / heme / porphvicene / corrole / myoglobin / peroxidase / oxygen affinity / supramolecular polymer |
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| Research Abstract |
Hemoproteins have one or several prosthetic groups in the protein matrix. In particular, protoheme IX which is one of the typical prosthetic groups is bound in the heme pocket via via non-covalent interaction. Therefore, it is possible to prepare an apoprotein under the acidic conditions and then insert an artificially created metal complex into the vacant heme pocket to obtain a reconstituted protein. To modify a function of a series of hemoproteins, our group has mainly focused on the substitution of the heme prosthetic group in this project. The summary of our recent results are shown as follows :
1. The myoglobin reconstituted with cobalt porphycene as an artificial prosthetic group showed high dioxygen affinity compared with the myoglobin with cobalt porphyrin.
2. The reconstituted myoglobin with the iron corrole showed peroxidase activity which is higher than that observed for the native myoglobin.
3. The horseradish peroxidase reconstituted with iron porphycene showed 10-fold larger activity toward guaiacol oxidation, and the highly oxidized species, compound I-like iron porphycene, was detectable.
4. The hybrid myoglobin which was prepared by heme-propionate modification and amino-acid mutation showed high peroxidase activity and is a good catalyst toward thioanisole oxidation.
5. The introduction of heme derivatives onto the hemoprotein surface gave a unique supramolecular hemoprotein fiber via intermolecular heme-heme pocket interaction.
These results suggest that the replacement of native heme with an artificially created prosthetic group will serve as a new way to create a functionalized hemoprotein.
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