Lysozymes have primarily a bacteriolytic function; those in tissues and body fluids are associated with the monocyte-macrophage system and enhance the activity of immunoagents. Lyz2 is active against a range of Gram-positive and Gram-negative bacteria. More effective than Lyz1 in killing Gram-negative bacteria. Lyz1 and Lyz2 are equally effective in killing Gram-positive bacteria. 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. Monomer. Expressed weakly in myeloblasts, moderately in immature macrophages, and strongly in both mature macrophages and macrophage-rich tissues. Mice display increased inflammation in response to M.luteus infection, impaired digestion of M.luteus cell walls, decreased clearance of P.aeruginosa from infected airways, increased susceptibility to K.pneumoniae infection and increased bacterial burden and mortality following infection with various Gram-negative bacteria. Lyz2 is non-immunogenic in wild-type mice but is rendered immunogenic in mutants. Lysozyme C is capable of both hydrolysis and transglycosylation; it shows also a slight esterase activity. It acts rapidly on both peptide-substituted and unsubstituted peptidoglycan, and slowly on chitin oligosaccharides. Belongs to the glycosyl hydrolase 22 family.