Involved in cell wall peptidoglycan recycling. Specifically cleaves the amide bond between the lactyl group of N-acetylmuramic acid and the alpha-amino group of the L-alanine in degradation products containing an anhydro N-acetylmuramyl moiety. Hydrolyzes the link between N-acetylmuramoyl residues and L-amino acid residues in certain cell-wall glycopeptides. Zn(2+) is required for amidase activity. Belongs to the N-acetylmuramoyl-L-alanine amidase 2 family.