Fruiting bodies were degraded themselves by the several glycoside hydrolases after spore releasing from mature fruiting bodies or harvesting. The enzymes involved in autolysis such as glucanase and chitinase have been studied. However, there are almost no information about the relationship between several glycoside hydrolases and autolysis. In this study, we studied to obtain the enzymatic properties of trehalase, and also to get the new information on the relationship between trehalase and autolysis. Crude enzymes were prepared from each fruiting body of Pleurotus sp. (from the immature stage to the autolysis stage) and the trehalase activities were measured at each growth stage. Trehalase activities sharply increased in autolysis stage. Trehalase was partially purified from fruiting bodies of the autolysis stage using various column chromatography and its properties were examined. The optimum temperature was 50 °C and the optimum pH was 4.5. In order to elucidate the localization of trehalase, fruit bodies of the autolysis stage were divided into the stipes and the pileuses, and the each trehalase activity was measured. High trehalase activities were found in the pileuses. Furthermore, in order to elucidate trehalase activities in autolysis more detail, the each fruiting body of autolysis progressing stages was finely divided into the stipes and the pileuses, and their activities were measured. The activities in the outer part of the pileuses were highest at the initial stage of autolysis and the activities shifted from the outer side to the inner side of the pileuses according to the progress of autolysis.

We have purified and characterized of metalloprotease metalloprotease from Nomuraea atypicola. N. atypicola was cultured in Sabouraud medium supplemented with powdered pupae. The metalloprotease from culture supernatant was purified to electrophoretically homogeneous state. The molecular mass of metalloprotease from N. atypicola was 50 kDa. The enzyme was most active at pH 8.5 and 40oC and stable at pH 5.0-7.0 and up to 40oC. The activity was inhibited by o-phenanthroline and EDTA. The N-terminal amino acid sequence of the enzyme showed a similarity to those of proteases (Metallo peptidase M36 family (Fungalysin)) from Coccidioides posadasii and Aspergillus fumigatus. The enzyme was found to be Fungalysin-like metalloprotease. cDNA encoding metalloprotease from N. atypicola was amplified by PCR using oligonucleotides deduced from the N-terminal endo peptide sequence, 5’- and 3’-RACE. Predicted enzyme structure consists of 637 amino acids with pro- and signal sequences. The mature enzyme had 391 amino acids and its deduced amino acid sequence coincided completely with the N- terminal amino end (20 amino acids) of metalloprotease purified from N. atypicola. We are studying on expression of the metalloprotease gene in Escherichia coli.

Effect of trehalose for the mycelial growth of Tricholoma matsutake were examined. When T. matsutake Z-1 strain was cultured in the partially modified matsutake liquid (PMML) medium and the Hamada matsutake liquid (HML) medium supplemented with trehalose at 24 ℃ for 80days, the vegetative mycelial dry weights showed higher value compared with those of PMML medium and HML medium supplemented with glucose (control). The range of the effect of 1.0-8.0% carbohydrate substrate on vegetative mycelial growth was investigated. The optimal concentration for mycelial growth was 2.0% for the glucose medium but 8.0% for the trehalose medium. To evaluate the potential of the production of trehalase from T. matsutake, the extracellular trehalase activity during the vegetative mycelial growth was measured. The activity of the extracellular trehalase increased during vegetative mycelial growth of T. matsutake and was maximal 70 days after inoculation. This extracellular enzyme was investigated for the purification and the characterization. The partially purified trehalase was obtained from about 1.53l static culture filtrate, with 19.1% recovery, and about 2,940 fold purification. The molecular mass was about 62.6kDa (SDS-PAGE) and 70kDa (Gel-filtration). The enzyme was most active around 40℃ and pH 5.0 and stable over a pH of 4.5~ 6.5 for 30min at 37℃. The enzyme readily hydrolyzed trehalose having α -1,1 glucosidic bond. However, it did not hydrolyze disaccharides such as maltose, iso-maltose, cellobiose, saccharose and lactose.