Lysozyme is an enzyme capable of breaking down the bacterial cell wall, and is typically used to enhance protein extractions or nucleic acid extractions. It works by hydrolyzing the 1,4-β-linkages located between theN-acetylmuramic acid and theN-acetyl-D-glucosamine residues in peptidoglycan.

Gram-positive cells have an increased susceptibility to the actions of lysozyme since gram-positive cells have a higher quantity of peptidoglycan in the cell wall. Gram-negative cells are less vulnerable, but can still be hydrolyzed in the presence ofEDTA.