Murein-degrading enzyme. May play a role in recycling of muropeptides during cell elongation and/or cell division. Exolytic cleavage of the (1->4)-beta-glycosidic linkage between N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) residues in peptidoglycan, from either the reducing or the non-reducing ends of the peptidoglycan chains, with concomitant formation of a 1,6-anhydrobond in the MurNAc residue. By SoxS. Belongs to the transglycosylase Slt family. Extended N-terminus.