title: Cloning, purification, and characterization of a thermostable alpha-L-arabinofuranosidase from Anoxybacillus kestanbolensis AC26Sari.
abstract: The gene, AbfAC26Sari, encoding an alpha-L-arabinofuranosidase from Anoxybacillus kestanbolensis AC26Sari, was isolated, cloned, sequenced, and characterized. On the basis of amino acid sequence similarities, this 57-kDa enzyme could be assigned to family 51 of the glycosyl hydrolase classification system. Characterization of the purified recombinant alpha-L-arabinofuranosidase produced in Escherichia coli BL21 revealed that it is active at a broad pH range (pH 4.5 to 9.0) and at a broad temperature range (45-85 degrees C) and it has an optimum pH of 5.5 and an optimum temperature of 65 degrees C. Kinetic experiment at 65 degrees C with p-nitrophenyl alpha-L-arabinofuranoside as a substrate gave a Vmax and Km values of 1,019 U/mg and 0.139 mM, respectively. The enzyme had no apparent requirement of metal ions for activity, and its activity was strongly inhibited by 1 mM Cu2+ and Hg2+. The recombinant arabinofuranosidase released L-arabinose from arabinan, arabinoxylan, oat spelt xylan, arabinobiose, arabinotriose, arabinotetraose, and arabinopentaose. Endoarabinanase activity was not detected. These findings suggest that AbfAC26Sari is an exo-acting enzyme.
authors.affiliation: Department of Biology, Faculty of Arts and Sciences, Karadeniz Technical University, 61080, Trabzon, Turkey. sabriye@ktu.edu.tr
authors.forename: Sabriye
authors.initials: S
authors.lastname: Canakci
authors.forename: Murat
authors.initials: M
authors.lastname: Kacagan
authors.forename: Kadriye
authors.initials: K
authors.lastname: Inan
authors.forename: Ali Osman
authors.initials: AO
authors.lastname: Belduz
authors.forename: Badal C
authors.initials: BC
authors.lastname: Saha
mesh_terms: D001406:Bacillaceae / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D003001:Cloning, Molecular; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D006026:Glycoside Hydrolases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D006358:Hot Temperature; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D006026:Glycoside Hydrolases; C019713:alpha-N-arabinofuranosidase