1998 Fiscal Year Final Research Report Summary
Development of Artificial Photosynthetic System by Functional Antbody Proteins.
| Project/Area Number |
09650875
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
生物・生体工学
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| Research Institution | OSAKA UNIVERSITY |
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Principal Investigator |
TAKAGI Masahiro Department of Biotechnology, Graduate School of Engineering, OSAKA UNIVERSITY Associate Professor, 大学院・工学研究科・応用生物工学専攻, 助教授 (00183434)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Antibody protein / Photo-induced hydrogen production / Photodynamic therapy / 光水素発生 |
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| Research Abstract |
The antibody L chain from Mab13-1 exhibits much higher peroxidase activity than TCPP Fe(III) alone.Furthermore, optimum temperature of the peroxidase reaction by the complex of 13-1L chain and TCPP Fe(III) was 90ﾟC, while that of the TCPP Fe(III) alone was 60ﾟC.Characterization of the mutant catalytic antibodies revealed that the hydrophobic region in the constant region (residue number 115-146) is important for high thermostability and the hydrophilic region (residue number 147-189) is important for high activity.Tertiary structure of this L chain catalytic antibody was predicted using a computer software AbM and the structure was compared with the strucure of the peroxidase from Arthromyces ramosus.Important His and Arg residues for the calytic activity were conserved in the antigen binding site of the L chain (His38, His94 and Arg96) and they were found in complementarity determining regions (CDR).Likewise, we have developed a new catalytic antibody (L-zyme), which exhibits peroxida
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se activity from anti-porphyrin antibody L-chain.We attempted to enhance photoinduced hydrogen production using a complex of the monoclonal antibody L chain and porphyrin molecule.When the complex of L chain and TCPP Zn(II) was used for reduction of methyl viologen, the comoplex exhibited better ability as a photosensitizer than TCPP Zn (II) alone.The electron transfer was coupled with hydrogenase and the complex could lead to production of more amount of hydrogen than TCPP Zn (II).Triplet lifetimes were measured and the complex exhibited longer lifetimes.
Based on these data we studied apoptosis of cancer cells induced by photodynamic therapy (PDT) using hematoporphyrin molecule.PDT induced apoptosis very effectively when HeLa cells are treated and signal transduction mechanism of PDT was similar to that of ultraviolet (UV) but DNA fragmentation and activation of INK kinase could not be observed in the case of PDT.Development of more effective method to induce apoptosis of carcinoma cells is in progess based on these experimental data Less
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