Oxidation of polycyclic aromatic hydrocarbons and dibenzo[p]-dioxins by Phanerochaete chrysosporium ligninase.
Oxidation of polycyclic aromatic hydrocarbons and dibenzo[p]-dioxins by Phanerochaete chrysosporium ligninase.
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DOI：
10.1016/s0021-9258(19)75982-1
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发表时间：
1986-12
期刊：
影响因子：
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通讯作者：
K. Hammel;B. Kalyanaraman;T. Kirk
中科院分区：
文献类型：
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作者：
K. Hammel;B. Kalyanaraman;T. Kirk
黄孢原毛平革菌的木质素过氧化物酶（木质素酶）催化多种木质素相关化合物的氧化。在这里，我们报告说，这种酶也催化氧化某些芳香族污染物和化合物与他们有关，包括多环芳烃的电离电位小于或等于约7.55 eV。这一结果表明，木质素过氧化物酶的H2 O2氧化态比经典过氧化物酶的类似状态更具氧化性。以芘为底物的实验表明，芘-1，6-二酮和芘-1，8-二酮是主要的氧化产物（高效液相色谱法测定占总量的84%），气相色谱/质谱分析表明，在H2（18）O存在下木质素酶催化芘氧化反应的醌氧来自于水。我们发现，整个培养的P. chrysosporium也瞬时氧化芘这些醌。二苯并[p]二恶英和2-氯二苯并[p]二恶英的实验表明，它们也是木质素酶的底物。二苯并[p]二恶英氧化的直接产物是二苯并[p]二恶英阳离子自由基，其在酶促反应中通过其电子自旋共振和可见吸收光谱观察到。因此，木质素酶的阳离子自由基机理不仅适用于木质素，而且适用于其他对环境重要的芳烃。
The lignin peroxidase (ligninase) of Phanerochaete chrysosporium catalyzes the oxidation of a variety of lignin-related compounds. Here we report that this enzyme also catalyzes the oxidation of certain aromatic pollutants and compounds related to them, including polycyclic aromatic hydrocarbons with ionization potentials less than or equal to approximately 7.55 eV. This result demonstrates that the H2O2-oxidized states of lignin peroxidase are more oxidizing than the analogous states of classical peroxidases. Experiments with pyrene as the substrate showed that pyrene-1,6-dione and pyrene-1,8-dione are the major oxidation products (84% of total as determined by high performance liquid chromatography), and gas chromatography/mass spectrometry analysis of ligninase-catalyzed pyrene oxidations done in the presence of H2(18)O showed that the quinone oxygens come from water. We found that whole cultures of P. chrysosporium also transiently oxidize pyrene to these quinones. Experiments with dibenzo[p]dioxin and 2-chlorodibenzo[p]dioxin showed that they are also substrates for ligninase. The immediate product of dibenzo[p]dioxin oxidation is the dibenzo[p]dioxin cation radical, which was observed in enzymatic reactions by its electron spin resonance and visible absorption spectra. The cation radical mechanism of ligninase thus applies not only to lignin, but also to other environmentally significant aromatics.