Bacillus subtilis N-acetylmuramic acid L-alanine amidase

J Biol Chem. 1975 Mar 10;250(5):1676-82.


The N-acetymuramic acid L-alanine amidase from Bacillus subtilis (ATCC 6051) has been purified to homogeneity. It is a monomeric protein of molecular weight 50,000. The enzyme has a high affinity for homologous cell walls and once attached to a cell wall will hydrolyze the wall completely before initiating the hydrolysis of a new cell wall. The affinity of the enzyme for cell walls devoid of teichoic acid or for cell walls of Bacillus megaterium is much lower than that for B. subtilis cell walls. A second homogenous protein has been isolated from B. subtilis which specifically combines with the amidase in a 1:1 molar ratio and stimulates enzyme activity. This modifier protein has no intrinsic cell wall lytic activity. The binding of enzyme and modifier protein has a dissociation constant of 8.5 times 10-9 M in 0.1 M LiCl, pH 8.0, but the two proteins can be completely dissociated in 3 M LiCl at pH 8.0.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alanine
  • Amidohydrolases / isolation & purification
  • Amidohydrolases / metabolism*
  • Bacillus subtilis / enzymology*
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism
  • Cations, Divalent / pharmacology
  • Cell Membrane / metabolism
  • Kinetics
  • Molecular Weight
  • Muramic Acids / analogs & derivatives
  • Protein Binding
  • Teichoic Acids / pharmacology


  • Bacterial Proteins
  • Cations, Divalent
  • Muramic Acids
  • Teichoic Acids
  • Amidohydrolases
  • Alanine