Some characteristics of extracellular proteinases from Coprinus cinereus

Spent culture medium contained five electrophoretically distinct proteolytic activities when Coprinus c;llereus was grown in culture medium which contained protein as sole source of nitrogen. The enzymes were separated by ultrafiltration, gel filtration and ionexchange chromatography into two groups designated EL and AD fractions. The EL fraction passed through a DE-52 column with eluant, and contained three electrophoretically distinct activities. The AD fraction was desorbed with 0'2 M-NaCI, and contained two electrophoretically distinct activities. Non-proteolytic protein bands were absent from the purified samples. Studies with inhibitors suggested the presence of cysteine, metalloand serine proteinases within the EL fraction. The EL enzyme activity was stable between pH 6 and pH II, and up to 30°C. Activity was optimal at pH 9, with a second peak at pH 6, and at 45°. The AD fraction may contain all four types of proteinases, with metalloand cystein enzymes being the major species. The AD enzymes were stable over broader ranges of pH (5-11) and temperature (up to 39°) than the EL proteinases, with optimum activities at pH 5 and 9, and at 56--62°. Both groups of enzymes had an apparent molecular weight of about 31 kDa, and isoelectric points of pH 4'9 (AD) and 5'6 (EL).