Isolation and characterization of two endoxylanases from Fusarium graminearum.
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 (5.5-9) than xlylanase 2 (5.5-7.5). Their temperature dependences were similar, >60% between 35 and 60 °C, with optimal temperatures of 45 °C for xylanase 1 and 50 °C for xylanase 2. Kinetic studies found that both enzymes had a lower K(m) for linear beachwood xylan than arabinoxylan. For xylanase 2, the V(max) increased with arabinoxylan, but decreased for xylanase 1.
Department of Plant Sciences, North Dakota State University, Fargo, North Dakota 58108-6050, United States.
Xinrong
X
Dong
Steven W
SW
Meinhardt
Paul B
PB
Schwarz
D004043:Dietary Fiber / Q000382:microbiology*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005670:Fusarium / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013696:Temperature
D004043:Dietary Fiber; D005656:Fungal Proteins; D043364:Endo-1,4-beta Xylanases