Isolation , purification and characterization of Benzo(a)pyrene degradation enzyme(s) from plants

• Main Authors: Wen-Hsuan Chen, 陳彣亘
• Other Authors: Shenq-Chyi Chang
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/94626237877742511616

碩士 === 國立陽明大學 === 生化暨分子生物研究所 === 94 === In recent years, we have make many pollutions in our environment, such as polycyclic aromatic hydrocarbons ( PAHs ) are mainly formed as the products of the incomplete combustion of fossil fuels and organic compounds. These pollutants consist of benzene homologs which have two or more fused aromatic rings, and most of those are more poison and hydrophobic with the number of ring increased. When their hydrophobic property is increased, it is hard to degrad them in the environment. The air pollutants such as NO、O3、CO2、SO2 could be uptaked and metabolized by some plants. However, it is still no report about the air pollutants: polycyclic aromatic hydrocarbons ( PAHs ) that could be absorbed and degraded by specific plants. In order to investigate the subject, five PAHs: fluorene, phenanthrene, anthracene, fluoranthene, benzo(a)pyrene were used as substrates for screening various extracts of leaves. We find Cuscuta sp. have the most significant PAHs degrading activity. The crude enzyme was subjected to a series of the purification procedures : cation exchanger column ( CM-Sephadex C-25 ), hydrophobic interaction column ( Phenyl-650M ) and gel filtration column ( Sephadex G-75 ), respectively. The Bap-degrading enzyme was purified 20 fold, giving a 38 % yield. The molecular weight of Bap-degrading enzyme estimated by SDS-PAGE was approximately 44 kDa. The optimal pH and temperature for this enzyme was pH 7.5 and 40℃. When the enzyme treated with distinct metal ions, most of the tested metal ions have no remarkable effects on the activity of the Bap-degrading enzyme, whereas the Cu2+ slightly inhibit it. In addition, the activity of the Bap-degrading enzyme was not affected by EDTA or β-mercaptoethanol