Extracellular proteinase spectrum ofAspergillus terreus grown on various substrates

The level of proteinase activity and the ratio of proteinases I and II, secreted byAspergillus terreus, a cellulase producer, was followed during its growth on media containing various carbon sources. Correlation was found between the level of proteinase secretion and the rate of change of the cellulase complex spectrum. The extracellular proteolytic system ofA. terreus was presented mainly by proteinase II (metalloproteinase) during cultivation under conditions favoring fast accumulation of low-molar mass cellulases. The results indicate that proteinase II could be responsible for the limited proteolysis of high-molar mass cellulases ofA. terreus into smaller enzymes of the cellulolytic complex, thus changing their substrate specificity.