ブドウ球菌の菌体外酵素に関する研究
第3報 病原ブドウ球菌同定のためのリゾチーム活性の測定条件
1968 年 23 巻 7 号 p. 465-472
詳細
1968 年 23 巻 7 号 p. 465-472
An attempt was made to obtain an aid for the identification of pathogenic staphylococci by using the routine agar plate method to check their lysozyme activity. This paper deals with basic conditions for the determination of the enzyme activity. The determination was made by the turbidity and the agar gel diffusion methods with the culture filtrate of the Smith strain of Staphylococcus aureus as enzyme solution and with acetone-dried cells of the ATCC 4698 strain of Micrococcus lysodeikticus as substrate. The following results were obtained.
1) In the turbidity method, it was demonstrated that the culture filtrate of the Smith strain after cultivation with shaking at 37°C for 24 hours possessed a lysozyme activity, and that the acetone-dried cells of the M. lysodeikticus strain were appropriate as substrate. The optimum pH was proved to be 6.5 in this system.
2) The enzyme activity was activated, to some extent, by sodium chloride in the range of 0.05-0.1M, but was completely inhibited at a molarity exceeding 0.3M. The enzymatic action was inactivated by heating at 100°C for 5 minutes or at 60-80°C for 10 minutes, so long as a culture filtrate of pH 7.8 was employed.
3) The enzyme activity was parallel to the grade of microbial growth, reaching its highest level at 18 hours of incubation. Thereafter it remained at the same level up to 72 hours of incubation.
4) Such lysozyme activity was also demonstrated by the agar gel diffusion method in a similar fashion.
