A 鈥測ellow鈥?laccase with 鈥渂lue鈥?spectroscopic features, from Sclerotinia sclerotiorum

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• 作者：Augustin C. Mo牛^a ; Marcel Pâ ; rvu^b ; Grigore Damian^c ; Florin D. Irimie^a ; Zsuzsanna Darula^d ; Katalin F. Medzihradszky^d ; Balazs Brem^a ; ^e ; Radu Silaghi-Dumitrescu^a ; ^{rsilaghi@chem.ubbcluj.ro}
• 关键词：Sclerotinia sclerotiorum ; Yellow laccase ; EPR spectroscopy ; UV&ndash ; vis spectroscopy
• 刊名：Process Biochemistry
• 出版年：2012
• 期刊代码：29_13595113
• 类别：bio
• 出版时间：June, 2012
• 卷：47
• 期：6
• 页码：968-975
• 文件大小：1451 K

摘要

Reported here are the production, purification and characterization of a laccase from the phytophathogenic fungus Sclerotinia sclerotiorum. This laccase is identified by mass spectrometry with a sequence coverage of 74.9%(458/577 AA) revealing that the protein is identical or highly homologous to a predicted oxidoreductase from this species (A7EM18 in the Uniprot database); the closest homologous protein previously isolated from a fungus is the Melanocarpus albomyces, with only 35%identity. The UV-vis spectral features of this laccase classify it as a 鈥測ellow鈥?one. The EPR spectrum nevertheless demonstrates resemblance to blue laccases - including the type 1 center not detectable in UV-vis spectra. The presence of type 3 coppers was proven by fluorescence spectrum and by 330 nm band in UV-vis. The purified laccase has an apparent molecular mass of 70 kDa and appears as a monomer. The values of K_M and k_cat were determined for ABTS, 2,6-dimethoxyphenol, p-phenylenediamine and guaicol and are typical of a laccase. The optimal pH value is around 4 except for ABTS, for which activity is linearly increasing with acidity. The high laccase activity in liquid culture makes S. sclerotiorum a useful source of laccase for practical applications.