Isolation and Characterization of Two Endoxylanases from Fusarium graminearum
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- 作者：Xinrong Dong ; Steven W. Meinhardt ; Paul B. Schwarz
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2012
- 出版时间：March 14, 2012
- 年：2012
- 卷：60
- 期：10
- 页码：2538-2545
- 全文大小：270K
- 年卷期：v.60,no.10(March 14, 2012)
- ISSN：1520-5118
文摘
This paper reports the first isolation from cultures of two endoxylanases secreted by Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schweinitz) Petch]. When F. graminearum is grown on wheat bran hydrated with a modified synthetic medium, high xylanase activity can be extracted. The two endoxylanases were identified by LC-MS/MS as the products of genes FGSG_6445 (Genbank gene id 2788192) (xylanase 1) and FGSG_3624 (GenBank accession no. AJ863566) (xylanase 2) with 61 and 51% sequence coverage, respectively. Both enzymes showed a pH optimum at pH 6, with xylanase 1 exhibiting a wider active pH range (5.5鈥?) than xlylanase 2 (5.5鈥?.5). Their temperature dependences were similar, >60% between 35 and 60 掳C, with optimal temperatures of 45 掳C for xylanase 1 and 50 掳C for xylanase 2. Kinetic studies found that both enzymes had a lower Km for linear beachwood xylan than arabinoxylan. For xylanase 2, the Vmax increased with arabinoxylan, but decreased for xylanase 1.