抄録
We purified yeast-Iytic enzymes from Rarobacter faecitabidus, a yeast-lytic coryneform bacterium isolated from a wastewater treatment system. The enzymes consisted of one β-1, 3-glucanase and two proteases. Molecular weights of the two proteases and β-1, 3-glucanase were 35, 000, 33, 000, and 82, 000 respectively by SDS polyacrylamide gel electrophoresis. The two proteases were serine proteases, which were inhibited by diisopropyl fluorophosphate or phenylmethylsulfonyl fluoride, and most active in alkaline pH. These proteases could decrease the turbidity of yeast suspensions. By this treatment, almost all yeast cells tested lost their viability, although the number of yeast cells did not decrease under microscopic observation. The β-1, 3-glucanase was most active at pH 5. This enzyme alone neither decreased the turbidity of yeast suspension nor affected the viability of yeast cells, but the β-1, 3-glucanase combined with one of the two proteases lysed yeast cells completely.
