Аннотация:An extracellular protease of filamentous fungus Alternaria alternata was purified 1300-fold with 8.3% yield by combination of affinity chromatography and gel filtration. Molecular weight of purified protease was 33 kD and optimal pH were 8.0 and 9.1 with BAPA and casein as the substrates, respectively. Optimal temperature of the protease was 48°C; the enzyme was stable below 30°C and was rapidly inactivated at higher temperatures. Inhibitor analysis indicates that the extracellular enzyme of A. alternata is serine proteinase. The study of substrate specificity of the enzyme indicates that it hydrolyzes substrates characteristic for trypsin-like proteases.