The Mechanism of Oxidation of Phenylhydrazine by Tyrosinase

• Main Authors: Sung, Yi-Ming, 宋益銘
• Other Authors: Wu, Shu-Pao
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/58379771635987736006

碩士 === 國立交通大學 === 分子科學研究所 === 97 === Direct oxidation of phenylhydrazine by tyrosinase was studied. The final product of oxidation of phenylhydrazine by tyrosinase or Cu(II) is phenol. Phenylhydrazine is not the natural substrates by tyrosinase. Kojic acid is the inhibitor with oxidation of phenylhydrazine by tyrosinase. By adding SOD (superoxide dismntase), the superoxide was removed, and the rate constants were enhanced. The evidences demonstrate that superoxide is generated in the reaction and retards the oxidation of phenylhydrazine. The removal of H2O2 by adding catalase slightly slows down the reaction. H2O2 is also an intermediate in the reaction and can facilitate the oxidation of phenylhydrazine. Addition of H2O2 in the reaction increases the rate constants. The oxidation of acetylphenyl- hydrazine by tyrosinase or Cu(II) was relatively slow, compared to that of phenylhydrazine. This is due to poor removal of proton form acetylphenylhydrazine by tyrosinase or Cu(II).