抄録
Properties of N-acetylmuramidase of Streptomyces rutgersensis H-46 were investigated using cell walls and peptidoglycan of Streptococcus feacalis as substrates. Peptidoglycan was prepared from cell walls by extracting polysaccharide, teichoic acid and protein with TCAand SDS. When cell walls and peptidoglycan were used as substrate for the enzyme, the enzyme reaction proceeded following second and zero order kinetics, respectively. The optimum pH for cell walls was 6.0, while that for peptidoglycan was 3.5. The enzyme activity was observed even at pH 1.3. It was found that the enzymereaction was strongly affected by ionic strength of the reaction mixture. Ionic strengths of 0.015 and 0.6 were found to be optimum when cell walls and peptidoglycan were used as substrate, respectively. An eminent difference in the extent of inhibition with metal ions was observed when the substrate of cell walls was replaced by peptidoglycan. It was considered that this difference was due to the presence of polysaccharide and/or teichoic acid in the cell wall preparation.
The respective apparent Km value and maximumreaction velocity of the enzyme for peptidoglycan of S. faecalis were calculated to be 22.0μg/ml and 0.067 absorbance/min.
