• Applied Biological Chemistry
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• v.40 no.5
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• pp.388-394
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• 1997

Extracellular protease (bassiasin I), from the culture filtrate of entomopathogenic fungus Beauveria bassiana ATCC7159, was successively purified by precipitation with ammonium sulfate followed by DEAE-Sephadex A-50, CM-cellulose and Hydroxyapatite column chromatography. A typical procedure provided 41-fold purification with 13.6% yield. The molecular weight of the purified pretense (bassiasin I) was found to be approximately 32,000 by SDS-PAGE. Isoelectric-focusing analysis of the enzyme showed a pI of 9.5. $NH_2-terminal$ sequence of the pretense showed homology with those of the fungal proteases. The enzyme has an optimal pH for activity at 10.5 and is stable over pH 5.0-11.0. The maximum activity of the enzyme was at $60-65^{\circ}C$, and approximately 20% activity remained at $60^{\circ}C$ after 120 min. The pretense was inhibited by phenylmethylsulfonyl fluoride (PMSF) and diisopropyl fluorophosphate (DIPF).