Hydrolytic properties of a thermostable α-L-arabinofuranosidase from Caldicellulosiruptor saccharolyticus.
OBJECTIVE
To characterize of a thermostable recombinant α-L-arabinofuranosidase from Caldicellulosiruptor saccharolyticus for the hydrolysis of arabino-oligosaccharides to l-arabinose.


RESULTS
A recombinant α-L-arabinofuranosidase from C. saccharolyticus was purified by heat treatment and Hi-Trap anion exchange chromatography with a specific activity of 28.2 U mg(-1). The native enzyme was a 58-kDa octamer with a molecular mass of 460 kDa, as measured by gel filtration. The catalytic residues and consensus sequences of the glycoside hydrolase 51 family of α-L-arabinofuranosidases were completely conserved in α-L-arabinofuranosidase from C. saccharolyticus. The maximum enzyme activity was observed at pH 5.5 and 80°C with a half-life of 49 h at 75°C. Among aryl-glycoside substrates, the enzyme displayed activity only for p-nitrophenyl-α-L-arabinofuranoside [maximum k(cat)/K(m) of 220 m(mol l(-1))(-1) s(-1)] and p-nitrophenyl-α-L-arabinopyranoside. This substrate specificity differs from those of other α-L-arabinofuranosidases. In a 1 mmol l(-1) solution of each sugar, arabino-oligosaccharides with 2-5 monomer units were completely hydrolysed to L-arabinose within 13 h in the presence of 30 U ml(-1) of enzyme at 75°C.


CONCLUSIONS
The novel substrate specificity and hydrolytic properties for arabino-oligosaccharides of α-L-arabinofuranosidase from C. saccharolyticus demonstrate the potential in the commercial production of L-arabinose in concert with endoarabinanase and/or xylanase.


CONCLUSIONS
The findings of this work contribute to the knowledge of hydrolytic properties for arabino-oligosaccharides performed by thermostable α-L-arabinofuranosidase.
Lim
Y-R
YR
Department of Bioscience and Biotechnology, Konkuk University, Seoul, Korea.
Yoon
R-Y
RY
Seo
E-S
ES
Kim
Y-S
YS
Park
C-S
CS
Oh
D-K
DK
D000595:Amino Acid Sequence; D001089:Arabinose / Q000378:metabolism; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006094:Gram-Positive Bacteria / Q000201:enzymology*; D006207:Half-Life; D006868:Hydrolysis; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
D009844:Oligosaccharides; D001089:Arabinose; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase