Baseplate central spike complex-associated lysozyme that is essential for the localized hydrolysis of bacterial cell wall, so that the tail tube, through which the phage DNA is ejected, can penetrate to the host inner membrane (PubMed:21129200, PubMed:21793574, PubMed:16956798, PubMed:3157805). The tail lysozyme complex at the tip of the tail tube penetrates through the outer membrane into the periplasm and during that process, gp5* dissociates from gp5C and activated (PubMed:16956798). Due to the lower pH in the periplasm, gp5* would dissociate from gp27 which probably still binds to the tip of the tube (PubMed:16956798). This way, lysozyme domain is released and locally digests the peptidoglycan layer to make a hole to let the tube penetrate to the inner membrane (PubMed:16956798). Involved in the tail assembly (PubMed:21129200). Hydrolysis of (1->4)-beta-linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in a peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrins. Optimum pH is 5.8. Monomer (PubMed:16956798). The central spike complex, which creates an extension of the tail tube, is made up of three copies of the gp27-gp5*-gp5C complex and one copy of gp5.4 (PubMed:11823865, PubMed:27193680). Part of the baseplate macromolecular complex which consists of gp5*, gp5C, gp5.4, gp27 (central spike complex); gp6, gp25, gp53 (inner baseplate); gp7, gp8 (intermediate baseplate); gp9, gp10, gp11, gp12 (peripheral); gp48 and gp54 (proximal region of the tail tube) (PubMed:27193680). Homotrimer (PubMed:11823865, PubMed:26295253). The central spike complex, which creates an extension of the tail tube, is made up of three copies of the gp27-gp5*-gp5C complex and one copy of gp5.4 (PubMed:11823865, PubMed:27193680). Part of the baseplate macromolecular complex which consists of gp5*, gp5C, gp5.4, gp27 (central spike complex); gp6, gp25, gp53 (inner baseplate); gp7, gp8 (intermediate baseplate); gp9, gp10, gp11, gp12 (peripheral); gp48 and gp54 (proximal region of the tail tube) (PubMed:27193680). Homotrimer. Present in 3 copies in the baseplate. Present in 3 copies in the baseplate. Present in the baseplate. In the fully assembled virus, gp5 precursor is cleaved to form the mature tail lysozyme gp5*, and a C-terminus fragment, gp5C (PubMed:10217762, PubMed:15342608, PubMed:15701513). The two fragments remain associated with the virion (PubMed:10217762, PubMed:15342608). The enzymatic activity of the precursor is about 10% of that of mature gp5* (PubMed:10217762). PubMed:15342608 reported a cleavage at Val-390 but the cleavage has been mostly observed at Ser-351 (PubMed:10217762, PubMed:15701513). Belongs to the glycosyl hydrolase 24 family.