AN EXTRACELLULAR PROTEASE FROM ASPERGILLUS FUMIGATUS

Abstract

An extracellular proteolytic enzyme produced by Aspergillus fumigatus has been isolated and purified. Preparations showed two distinct peaks of activity when allowed to act on proteins buffered at different pH's (pH 7 and 10 with casein and pH 4 and 9 with hemoglobin). Although this might suggest the presence of distinct neutral and alkaline proteases, all other observations (column chromatography, electrophoresis, heat inactivation, etc.) indicated that a single enzyme was involved. The enzyme hydrolyzed polyglutamic acid and polylysine optimally at about pH 4 and 10 respectively, with the rate of hydrolysis of pofyglutamic acid being about 10 times that of polylysine. The products of digestion of polyamino acids were the corresponding peptides, no trace of monomer being found.