Lysis of bacterial host cell wall. Hydrolyzes the link between N-acetylmuramoyl residues and L-amino acid residues in certain cell-wall glycopeptides. Binds to the choline residues present in the cell wall substrate. May have a use in the prevention of pneumococcal disease. Pal acts very effectively in killing 15 common serotypes of pneumococci, including highly penicillin-resistant strains. It could be used to eliminate the nasopharyngeal reservoir of these bacteria. Belongs to the peptidase C40 family.