Characterization of a recombinant beta-glucosidase from the thermophilic bacterium Caldicellulosiruptor saccharolyticus.
A recombinant beta-glucosidase from Caldicellulosiruptor saccharolyticus DSM 8903 with a specific activity of 13 U/mg was purified by heat treatment and His-Trap affinity chromatography and identified as a single 54 kDa band on SDS-PAGE. The molecular mass of the native enzyme was 108 kDa as a dimer by gel filtration. beta-Glucosidase showed optimum activity at pH 5.5 and 70 degrees C for p-nitrophenyl (pNP)-beta-d-glucopyranoside. The half-lives of the enzyme at 60, 70, and 80 degrees C were 250, 24.3, and 0.4 h, respectively. The enzyme exhibited catalytic efficiency and specific activity for pNP-beta-d-fucopyranoside, pNP-beta-d-glucopyranoside, and pNP-beta-d-galactopyranoside in decreasing order among aryl-beta-glycosides, but not for aryl-alpha-glycosides. Cello-oligosaccharides from n = 2 to 5 as substrates using 4 mM each sugar and 3 U/mg of enzyme were completely hydrolyzed to glucose at 70 degrees C within 16 h.
Hong
Mi-Ri
MR
Department of Bioscience and Biotechnology, Konkuk University, Gwangjin-gu, Seoul 143-701, Republic of Korea.
Kim
Yeong-Su
YS
Park
Chang-Su
CS
Lee
Jung-Kul
JK
Kim
Yeong-Suk
YS
Oh
Deok-Kun
DK
D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature; D046950:Thermoanaerobacterium / Q000235:genetics*; D001617:beta-Glucosidase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism
D011994:Recombinant Proteins; D001617:beta-Glucosidase