β-d-Xylosidase production was maximal for Humicola grisea var. thermoidea grown on xylan as the sole carbon source. The main β-d-xylosidase activity was localised in the periplasm. β-Xylosidase was purified from crude extracts by heat treatment, ammonium sulfate precipitation and chromatography on DEAE-cellulose and Sephadex G-100. The purified enzyme was a monomer of molecular mass estimated to be 43 kDa by SDS-PAGE and gel filtration. Optima of pH and temperature were 6.0 and 50 °C, respectively. The enzyme activity was stimulated by Ca2+, Fe2+, and Mg2+. The purified β-xylosidase did not exhibit xylanase, carboxymethylcelullase, galactosidase, glucosidase, fucosidase or arabinosidase activities. The purified β-xylosidase hydrolysed xylobiose and xylo-oligosaccharides of up to five monosaccharide units. The enzyme had a Km of 0.49 mM for p-nitrophenyl-β-d-xylopyranoside and was not inhibited by its product, xylose. © 1995.
de Almeida, E. M., Polizeli, M. de L. T. M., Terenzi, H. F., & Atilio Jorge, J. (1995). Purification and biochemical characterization of β-xylosidase from Humicola grisea var. thermoidea. FEMS Microbiology Letters, 130(2–3), 171–175. https://doi.org/10.1016/0378-1097(95)00200-O