Purification, characterization and amplification of a 1.8 kbp fragment of xylanase 5 from <i>Aeromonas caviae </i>W-61

Abstract

<i>Aeromonas caviae </i>W-61 produces multiple extracellular xylanases, the xylanases 1,2,3,4, and 5. In this study, we purified and characterized the xylanase 5 of <i>A. caviae </i>W-61, and amplified a part of xylanase 5 gene (<i>xyn5</i>)<i>. </i>The purified xylanase 5 was found to be a single polypeptide with molecular mass of 140 kDa. It was an endo-β-1 ,4-xylanase showing

optimum temperature 40^oC and optimum <i>p</i>H<i> </i>6.0. Xylobiose, xylotriose, xylotetrose, xylopentose, xylohexose and a small amount of xylose were detected as the hydrolysis products. The N-terminal amino acid sequence and several internal amino acid sequences of xylanases 5 were determined. From the sequence, a 1.8 kbp fragment was amplified by PCR using forward and reverse primers. DNA sequencing confirmed the presence of nucleotide sequences corresponding to the N-terminal amino acid sequence and the internal amino acid sequences of xylanase 5.