Cell-wall hydrolase that hydrolyzes the amide bond between N-acetylmuramic acid and L-alanine in cell-wall glycopeptides. Is able to lyse whole mycobacteria, release peptidoglycan from the cell wall of M.luteus and M.smegmatis, and cleave N-acetylmuramoyl-L-alanyl-D-isoglutamine, releasing free N-acetylmuramic acid and dipeptide. Hydrolyzes the link between N-acetylmuramoyl residues and L-amino acid residues in certain cell-wall glycopeptides. Optimum pH is 7.5. Activity is greater than 50% of maximal from pH 6.2 to 9.2. Is stable throughout a broad range of pH (6-10). Cell wall degradation; peptidoglycan degradation. Belongs to the N-acetylmuramoyl-L-alanine amidase 3 family.