Characteristics of an intracellullar proteinase system of a Trichosporon species isolated from Trappist-type cheese.

A greater yield of the active principle was obtained when the cells were allowed to autolyze than when mechanical methods of cell disruption were used. A marked increase in activity was obtained when the crude cell extracts were held for 18 hr at 25 C after acidification to pH 5.0. The activated enzyme was partially purified by precipitation with 95% ethanol. This partially purified extract was most active at pH 5.8, and showed activity over a temperature range of 10 to 42 C. Its rate of activity was markedly decreased by sulfhydryl-binding agents. It exhibited its greatest degree of thermostability at pH 5.0.