title: A phage-associated murein hydrolase in Streptococcus pneumoniae infected with bacteriophage Dp-1.
abstract: A phage-associated murein hydrolase activity capable of degrading pneumococcal cell walls was isolated and purified to homogeneity from the phage-induced lysate of an autolysis-defective pneumococcal mutant infected with the bacteriophage Dp-1. Some properties of the enzyme resembled those of the wild-type (host) pneumococcal murein hydrolase: cell walls prepared from ethanolamine-grown pneumococci were resistant to the enzyme; the activity was inhibited by the Forssman antigen and was sensitive to proteolytic enzymes. The phage-associated enzyme was not inhibited by antiserum prepared against the purified pneumococcal murein hydrolase; the activity was stimulated by reducing agents and was partially inhibited by cardiolipin. The subunit molecular weight of the phage-associated enzyme was somewhat smaller (31 000) than that of the pneumococcal hydrolase (35 000). This appears to be the first description of a phage-associated murein hydrolase activity in pneumococci.
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism*; D001433:Bacteriolysis; D001435:Bacteriophages / Q000201:enzymology* / Q000502:physiology; D002473:Cell Wall / Q000201:enzymology; D002850:Chromatography, Gel; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D009154:Mutation; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D013296:Streptococcus pneumoniae / Q000201:enzymology* / Q000502:physiology; D013696:Temperature
chemical_list: D000581:Amidohydrolases; D009238:N-Acetylmuramoyl-L-alanine Amidase