Substrate profile by Laccase

• Main Authors: Liao,Yu-Huei, 廖昱惠
• Other Authors: Lai,Chi-Yung
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/v7ppwu

碩士 === 國立彰化師範大學 === 生物技術研究所 === 105 === Laccase are multi-copper oxidases (MCO)that play a major role in nature in degrading lignin in plant cell walls.Lignin is polymerized from aromatic monomers and other aromatic compounds that are mostly substrates of laccase-catalyzed reduction-oxidation(Redox) reations.Laccase performs a one-eletron oxidation and uses oxygen as the eletron acceptor which is eventully reduced to water. Most previous studies on the kinetics of laccase measure the absorption spectra of the products,and kinetic parameters of the enzyme were calculated from the changes of the absorption spectrum. However, some of the products of laccase-catalyzed reations are unstable and these unstable products can react with each other to form one or more stable compounds that interfere with the measurement of the enzyme-catalyzed reaction. In addition, the absorption spectrometry determination need a change in color to measure the enzyme reations , but not all substrates of laccase produce a color chang upon oxidation.As oxygen in the reation solution was consumed when laccase catalyzed the oxidation of its substrates, we used dissolved oxygen meter to estimate the enzyme kinetic parameters of laccase. Three types of laccase and sixteen kinds of substrate enzyme activity test were used and were classified based on the reaction results.The aim of this study is to find the best substrate for each enzyme to facilitate the studies of these laccase enzymes. Key word:laccase、substrate、DO meter