Characterization of an acid-labile, thermostable β-glycosidase from Thermoplasma acidophilum

• Published in: Biotechnology letters 2009-09, Vol.31 (9), p.1457-1462
• Main Authors: Kim, Hye-Jung, Park, Ah-Reum, Lee, Jung-Kul, Oh, Deok-Kun
• Format: Article
• Language: English
• Subjects: Applied Microbiology; Archaeal Proteins - chemistry; Archaeal Proteins - isolation & purification; Archaeal Proteins - metabolism; beta-galactosidase; beta-Glucosidase - chemistry; beta-Glucosidase - isolation & purification; beta-Glucosidase - metabolism; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Dimerization; Enzyme Stability; Fundamental and applied biological sciences. Psychology; Half-Life; Hydrogen-Ion Concentration; Life Sciences; Microbiology; Molecular Weight; Original Research Paper; Recombinant Proteins - chemistry; Recombinant Proteins - isolation & purification; Recombinant Proteins - metabolism; Substrate Specificity; Temperature; thermal stability; Thermoplasma - isolation & purification
• ISSN: 0141-5492; 1573-6776
• DOI: 10.1007/s10529-009-0018-1

A recombinant putative β-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°C. The enzyme was unstable below pH 6.0: at pH 6 its half-life at 75°C was 28 days but at pH 4.5 was only 13 h. Catalytic efficiencies decreased as p-nitrophenyl(pNP)-β-d-fucopyranoside (1067) > pNP-β-d-glucopyranoside (381) > pNP-β-d-galactopyranoside (18) > pNP-β-d-mannopyranoside (11 s⁻¹ mM⁻¹), indicating that the enzyme was a β-glycosidase.