Purification and Some Properties of Carboxyl Proteinase in Mycelium of Lentinus edodes

Abstract

The effect of Streptomyces-pepsin inhibitor (S-PI) on fruit-body formation of Lentinus edodes (Berk.) Sing. was studied. The addition of S-PI to the culture medium(510 μg/ml) shortened the time required for mature fruit-bodies, and increased the fruiting-percentage and the overall yield 3.4 times compared to the control.
The intracellular proteinase in the mycelium was investigated. Proteinases having an optimal pH of 2.7 and 7.0 were found in the vegetative mycelial extract. When S-PI was added to the culture medium, their activities were strikingly changed; the carboxyl proteinase activity was remarkably decreased, and, in the contrary, the metal proteinase activity was increased to 1.5 times that of the control.
The carboxyl proteinase was purified. This enzyme was strongly inhibited by S-PI and synthetic pepsin inhibitors such as DAN and EPNP. The molecular weight and isoelectric point were 43, 000 and pH 3.4, respectively.