Characterization of an acid-labile, thermostable beta-glycosidase from Thermoplasma acidophilum.
A recombinant putative beta-galactosidase from Thermoplasma acidophilum was purified as a single 57 kDa band of 82 U mg(-1). The molecular mass of the native enzyme was 114 kDa as a dimer. Maximum activity was observed at pH 6.0 and 90 degrees C. The enzyme was unstable below pH 6.0: at pH 6 its half-life at 75 degrees C was 28 days but at pH 4.5 was only 13 h. Catalytic efficiencies decreased as p-nitrophenyl(pNP)-beta-D-fucopyranoside (1067) > pNP-beta-D-glucopyranoside (381) > pNP-beta-D-galactopyranoside (18) > pNP-beta-D-mannopyranoside (11 s(-1) mM(-1)), indicating that the enzyme was a beta-glycosidase.
Kim
Hye-Jung
HJ
Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea.
Park
Ah-Reum
AR
Lee
Jung-Kul
JK
Oh
Deok-Kun
DK
D019843:Archaeal Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D019281:Dimerization; D004795:Enzyme Stability; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D013696:Temperature; D013822:Thermoplasma / Q000302:isolation & purification*; D001617:beta-Glucosidase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*
D019843:Archaeal Proteins; D011994:Recombinant Proteins; D001617:beta-Glucosidase