A novel white laccase from Pleurotus ostreatus
A novel white laccase from Pleurotus ostreatus
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DOI：
10.1074/jbc.272.50.31301
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发表时间：
1997-12-12
影响因子：
4.8
通讯作者：
Sannia, G
中科院分区：
文献类型：
--
作者：
Palmieri, G;Giardina, P;Sannia, G
两种漆酶同工酶POXA 1和POXA 2是具有3和9%碳水化合物含量的单体糖蛋白，通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳，分子量为约61和67 kDa，通过天然条件下的凝胶过滤，分子量为约54和59 kDa，和61 kDa的基质辅助激光解吸电离质谱法（仅对POXA 1）和pI值分别为6.7和4.0。已经对POXA 1的N末端和三个胰蛋白酶肽进行了测序，揭示了与来自其他微生物的漆酶的明显同源性，而POXA 2显示封闭的N末端，POXA 2作为温度的函数的稳定性特别低，而POXA 1相对于pH和温度显示出显著的高稳定性。（2，2 ′-连氮基-双（3-乙基苯并噻唑啉-6-磺酸））与各种不同的取代酚和芳族胺一起伴随氧的还原，但POXA 1不能氧化愈创木酚，紫外/可见吸收光谱、原子吸收光谱和极谱数据表明，POXA 2分子中含有4个铜原子，而POXA 1分子中只有1个铜、2个锌和1个铁原子。POXA 1漆酶的中性pI和异常金属含量使其具有独特的结构特征。在600 nm处缺乏典型的吸光度，使其被分类为“白色”漆酶。
Two laccase isoenzymes (POXA1 and POXA2) produced by Pleurotus ostreatus were purified and fully characterized, POXA1 and POXA2 are monomeric glycoproteins with 3 and 9% carbohydrate content, molecular masses of about 61 and 67 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis, of about 54 and 59 kDa by gel filtration in native conditions, and of 61 kDa by matrix-assisted laser desorption ionization mass spectrometry (only for POXA1) and pI values of 6.7 and 4.0, respectively, The N terminus and three tryptic peptides of POXA1 have been sequenced, revealing clear homology with laccases from other microorganisms, whereas POXA2 showed a blocked N terminus, The stability of POXA2 as a function of temperature was particularly low, whereas POXA1 showed remarkable high stability with respect to both pH and temperature.Both enzymes oxidize syringaldazine and ABTS (2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) together with a variety of different substituted phenols and aromatic amines with the concomitant reduction of oxygen, but POXA1 is unable to oxidize guaiacol, Both enzymes were strongly inhibited by sodium azide and thioglycolic acid but not by EDTA.UV/visible absorption spectra, atomic adsorption, and polarographic data indicated the presence of 4 copper atoms/mol of POXA2 but only one copper, two zinc, and one iron atoms were found/mol of POXA1.The neutral pI and the anomalous metal content of POXA1 laccase render this enzyme unique in its structural characteristics. The lack of typical absorbance at 600 nm allows its classification as a ''white'' laccase.