Enzyme Kinetics Research of Laccases Using Dissolved Oxygen Meter
碩士 === 國立彰化師範大學 === 生物技術研究所 === 102 === Laccase ( EC 1.10.3.2 ) are multi-copper oxidases ( MCO ) that are found in many plants, fungi, and microorganisms. Laccases act on phenols and similar molecules, performing an one-electron oxidation and taking oxygen as the electron acceptor which is eventua...
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| Format: | Others |
| Language: | zh-TW |
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2014
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| Online Access: | http://ndltd.ncl.edu.tw/handle/8j5t44 |
| Summary: | 碩士 === 國立彰化師範大學 === 生物技術研究所 === 102 === Laccase ( EC 1.10.3.2 ) are multi-copper oxidases ( MCO ) that are found in many plants, fungi, and microorganisms. Laccases act on phenols and similar molecules, performing an one-electron oxidation and taking oxygen as the electron acceptor which is eventually reduced to water. The natural substrate of laccase is lignin. Laccases play a role in the degradation of lignin, and transform lignin’s monomers and many other aromatic compounds by oxidation-reduction reactions. The traditional laccase assay uses spectrophotometry to measure the absorbance of products for estimating enzyme kinetic parameters. This method can be problematic in that the products of enzyme-catalyzed reaction are often unstable and can be converted to other compounds by non-enzymatic reactions. The absorbance of these compounds can interfere with spectrophotometric readings and makes estimates of kinetic parameters untrustworthy. To resolve the problems of spectrophotometry, we try to estimate enzyme kinetic parameters of laccases by measuring oxygen consumption using dissolved oxygen meter. The major advantage of dissolved oxygen measurement is that its readings directly correspond to the oxidation-reduction reaction catalyzed by laccases, and enzyme activity can be directly determined from DO changes without any knowledge of product identities and their spectrophotometric properties. We compared the results obtained from traditional spectrophotometry and dissolved oxygen meter and found that the latter produced more robust estimates of kinetic parameters for a large number of substrates.
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