Purification and properties of the beta-glucosidase from a nitrile hydratase-producing Brevibacterium sp. strain R312.

Besides its nitrile hydratase and wide spectrum amidase activities, the Brevibacterium sp. R312 strain also possesses a constitutive beta-glucosidase. Its optimum pH is 6. The enzyme was purified by fractionation precipitation with ammonium sulfate followed by chromatographic elutions on Q-Sepharose Fast Flow, Sephadex G-200 and Phenyl Superose. The resulting purification was 1960 folds for a 6% yield. The molecular weight of this enzyme was estimated at 180,000. It contains two identical sub-units. The pI is 5.5. This enzyme has a strong affinity for aryl-beta-glycosides:pNPG, prunassine; it could also degrade linamarine. It is inhibited by p-chloromercuribenzoate, delta-gluconolactone and glucose.