Functionalization of Myoglobin to Peroxidase by Modified Heme Reconstitution Method.
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Accession number;04A0258617
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| Title;Functionalization of Myoglobin to Peroxidase by Modified Heme Reconstitution Method. |
| Author;
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Journal Title;Abstracts. Symposium on Biofunctional Chemistry
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Journal Code:L0836A
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ISSN:
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VOL.18th;NO.;PAGE.70-71(2003)
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| Figure&Table&Reference;FIG.2, REF.3 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;An oxygen storage hemoprotein, myoglobin, has very little peroxidase activity, because it has no specific substrate binding site. In the present study, to convert myoglobin into an active peroxidase, native heme of the hemoprotein was replaced with a chemically-modified heme having two aromatic rings at the propionate termini. The reconstituted myoglobin was examined for 2-methoxyphenol (guaiacol) oxidation in the presence of H2O2 and it showed 16-fold smaller Km value and 34-fold greater kcat/Km value compared with native myoglobin. Moreover, we hybridized the prosthetic group modification and amino acid mutation methods to construct a modified myoglobin with much higher peroxidase activity. Remarkable increase of peroxidase activity of the obtained myoglobin variants, especially a reconstituted H64D mutant myoglobin with the artificial heme, suggests that the modified heme reconstitution offers a hydrophobic domain to enhance substrate binding and the distal histidine mutation makes appropriate heme distal environments to increase peroxidase activity. Combination of the modified heme reconstitution and the amino acid mutation should be useful to enhance activity of other hemoproteins. (author abst.) |
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