A search for ligninolytic peroxidases in the fungus pleurotus eryngii involving alpha-keto-gamma-thiomethylbutyric acid and lignin model dimers
A search for ligninolytic peroxidases in the fungus pleurotus eryngii involving alpha-keto-gamma-thiomethylbutyric acid and lignin model dimers
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杏鲍菇中涉及α-酮-γ-硫甲基丁酸和木质素模型二聚体的木质素分解过氧化物酶的研究
DOI：
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发表时间：
1999
影响因子：
4.4
通讯作者：
Martínez
中科院分区：
文献类型：
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作者：
Caramelo;Martínez
由于存在一些关于由侧耳属物种产生的木质素分解酶的争议，因此如先前针对黄孢原毛革菌木质素过氧化物酶（LiP）所描述的从α-酮-γ-硫甲基丁酸（KTBA）释放的乙烯被用于评估侧耳属培养物和细胞外蛋白的氧化能力。木质素模型二聚体用于确认从液体和固态发酵（SSF）培养物中分离的酶的木质素分解能力。鉴定了在藜芦醇和H2 O2存在下氧化KTBA的三种蛋白质（在液体培养物中发现两种蛋白质，在SSF培养物中发现一种蛋白质）。这些蛋白质是多功能的过氧化物酶，作用于Mn 2+，以及简单的酚和藜芦醇。从液体培养物中获得的两种过氧化物酶能够降解非酚β-O-4二聚体，产生藜芦醛，以及不能被P. chrysosporium过氧化物酶有效氧化的酚二聚体。前一个反应是LiP的特征反应。第三KTBA-氧化过氧化物酶氧化的酚二聚体（在Mn 2+的存在下）。最后，在SSF培养物中鉴定了第四种Mn 2+氧化过氧化物酶，其基于其在Mn 2+存在下氧化KTBA的能力。该酶与P. chrysosporium的Mn依赖性过氧化物酶相关，因为它不表现出与藜芦醇的活性和与二聚体的Mn非依赖性活性。这些结果表明，P. erynalgum产生三种类型的过氧化物酶，其具有氧化木质素的能力，但缺乏典型的LiP。类似的酶（就N-末端序列和催化性质而言）由其他的Plepherus物种产生。一些结构方面的P. eryntophan过氧化物酶的催化性能进行了讨论。
Because there is some controversy concerning the ligninolytic enzymes produced by Pleurotus species, ethylene release from alpha-keto-gamma-thiomethylbutyric acid (KTBA), as described previously for Phanerochaete chrysosporium lignin peroxidase (LiP), was used to assess the oxidative power of Pleurotus eryngii cultures and extracellular proteins. Lignin model dimers were used to confirm the ligninolytic capabilities of enzymes isolated from liquid and solid-state fermentation (SSF) cultures. Three proteins that oxidized KTBA in the presence of veratryl alcohol and H2O2 were identified (two proteins were found in liquid cultures, and one protein was found in SSF cultures). These proteins are versatile peroxidases that act on Mn2+, as well as on simple phenols and veratryl alcohol. The two peroxidases obtained from the liquid culture were able to degrade a nonphenolic beta-O-4 dimer, yielding veratraldehyde, as well as a phenolic dimer which is not efficiently oxidized by P. chrysosporium peroxidases. The former reaction is characteristic of LiP. The third KTBA-oxidizing peroxidase oxidized only the phenolic dimer (in the presence of Mn2+). Finally, a fourth Mn2+-oxidizing peroxidase was identified in the SSF cultures on the basis of its ability to oxidize KTBA in the presence of Mn2+. This enzyme is related to the Mn-dependent peroxidase of P. chrysosporium because it did not exhibit activity with veratryl alcohol and Mn-independent activity with dimers. These results show that P. eryngii produces three types of peroxidases that have the ability to oxidize lignin but lacks a typical LiP. Similar enzymes (in terms of N-terminal sequence and catalytic properties) are produced by other Pleurotus species. Some structural aspects of P. eryngii peroxidases related to the catalytic properties are discussed.