The beta-xylosidase of Thermomonospora.

This study is concerned with characterizing cell-bound inducible beta-xylosidase produced by a strain of the thermophilic bacterial genus Thermomonospora. A crude preparation of this enzyme recovered from sonicated cells of this organism displayed high activity against paranitrophenyl-beta-xylopyranoside over a pH range of 5.5-7.7. The temperature optimum, based on a 30-min assay of activity, at pH 6.5 was 70 degrees C. The crude enzyme had a thermal half-life of approximately 1 week at 55 degrees C and pH 6.5. Xylose inhibited the enzyme. Values of K(m) and V(max) are estimated from the reaction rate data as 0.82 mM and 8 U/L, respectively.