Purification and some properties of an alkaline xylanase from alkaliphilic Bacillus sp. strain 41M-1.
An alkaliphilic Bacillus sp. strain, 41M-1, isolated from soil produced multiple xylanases extracellularly. One of these xylanases was purified to homogeneity by ammonium sulfate fractionation and anion-exchange chromatography. The moleculr mass of this enzyme (xylanase J) was 36 kDa, and the isoelectric point was pH 5.3. Xylanase J was most active at pH 9.0. The optimum temperature for the activity at pH 9.0 was around 50 degrees C. The enzyme was stable up to 55 degrees C at pH 9.0 for 30 min. Xylanase J was completely inhibited by the Hg2+ion and N-bromosuccinimide. The predominant products of xylan hydrolysate were xylobiose, xylotriose, and higher oligosaccharides, indicating that the enzyme was an endoxylanase. The apparent Km and Vmax values on xylan were 3.3 mg/ml and 1,100 micromol-1 mg-1, respectively. Xylanase J showed high sequence homology with the xylanases from Bacillus pumilus and Clostridium acetobutylicum in the N-terminal region. Xylanase J acted on neither crystalline cellulose nor carboxymethyl cellulose, indicating a possible application of the enzyme in biobleaching processes.
Nakamura
S
S
Department of Bioengineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 227, Japan.
Wakabayashi
K
K
Nakai
R
R
Aono
R
R
Horikoshi
K
K
D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology*; D043364:Endo-1,4-beta Xylanases; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D006358:Hot Temperature; D008969:Molecular Sequence Data; D010600:Pharmacology; D012988:Soil Microbiology; D014990:Xylans / Q000378:metabolism
D014990:Xylans; D006026:Glycoside Hydrolases; D043364:Endo-1,4-beta Xylanases