Proteolysis In Vivo and In Vitro in the White Rot Fungus Trametes Versicolor: Insight into the Control of Laccase Activity, 1997 Biological Sciences Symposium Proceedings

The results obtained from the studies of in vivo and in vitro proteolysis in the white rot fungus Trametes versicolor support the view that proteolytic enzymes, including serine proteinases, play an important role in the control of laccase activity, the enzyme which is involved in biotransformation of lignin by the fungus. In experimentswith specific inhibitors added to the cultures of T. versicolor: phenyhnethylsulphonyl fluoride (PMSF) and chloroquine distinct changes in laccase activity were observed both under nitrogen- and carbon-starvation conditions. These changes were accompaniedby markedly altered patterns of proteolytic activities revealed by electrophoretic analysis with haemoglobin-containing polyacrylamidegels. Contrary to the starvation conditions the inhibitors had no effect on laccase activity in nutrient-rich cultures of T. versicolor. In vitro experiments with limited proteolysis of T. versicolor laccase using intracellular and extracellular serine proteinases isolated from the fungus revealed a short-term “super-activation” of laccase followed by inactivation of the enzyme. From the results gained about changes in the activity of laccase paralleled with changes of activities of proteases in vivo as well as temporal activation of laccase by serine proteinases in vitro, the control of laccase activity may be partly ascribed to proteolytic enzymes. Although adapted to laboratory conditions, this approach is potentially applicable in biotechnological processes involving laccase