Evidence for the presence of a second peptidoglycan hydrolase in Streptococcus faecium

Extracellular and cellular distribution of muramidase-2 and muramidase-1 of Enterococcus hirae ATCC 9790

“…Both enzyme activities dissolve the re-Nacetylated peptidoglycan of E. hirae (18). Furthermore, again in contrast to M-1, M-2 fails to bind to concanavalin A-Sepharose and fails to stain with the periodate-Schiff reagent, suggesting that it is not glycosylated (18).…”

“…Although high levels of muramidase-2 activity were present in supernatants of stationary-phase cultures, the bacteria were resistant to autolysis. Thus it appears that the peptidoglycan in walls of intact cells of E. hirae is somehow protected from the hydrolytic action of extracellular muramidase-2.Enterococcus hirae ATCC 9790 (formerly Streptococcus faecium) was shown to possess two separate and distinct peptidoglycan hydrolase activities; both enzymes are N-acetylmuramoylhydrolases (muramidases) (18,29). Both enzymes are high-molecular-weight, complex proteins that possess a number of rather unusual properties, especially in contrast to avian and bacteriophage lysozymes that hydrolyze the same bond in the cell wall peptidoglycan.…”

“…Enterococcus hirae ATCC 9790 (formerly Streptococcus faecium) was shown to possess two separate and distinct peptidoglycan hydrolase activities; both enzymes are N-acetylmuramoylhydrolases (muramidases) (18,29). Both enzymes are high-molecular-weight, complex proteins that possess a number of rather unusual properties, especially in contrast to avian and bacteriophage lysozymes that hydrolyze the same bond in the cell wall peptidoglycan.…”

“…Muramidase-2 (M-2) was partially purified from the supernatant culture medium and was shown to be a 70-to 75-kDa protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) (18). M-2 was also purified to apparent homogeneity from the insoluble pellet of disrupted E. hirae (7).…”

“…In contrast to M-1, it rapidly dissolves cell walls of Micrococcus luteus and dissolves the peptidoglycan fraction of E. hirae cell walls. However, M-2 has little ability to dissolve E. hirae cell walls, which are a good substrate for purified M-1 activity (18). Both enzyme activities dissolve the re-Nacetylated peptidoglycan of E. hirae (18).…”