Question

Why Lysozyme, an enzyme that can digest the NAG-NAM linkages in peptidoglycan, is more effective against Gram-positive bacteria?

Answer 1

Bacterial cell walls are of two types: Gram negative and Gram positive. Gram positive bacteria have a cell wall composed of a thick layer of peptidoglycan overlaid by a thinner layer of techoic acid. In contrast, Gram negative bacteria have a thinner layer of peptidoglycan which is enclosed in a second lipid bilayer. Lysozyme is most effective against Gram positive bacteria since the peptidoglycan layer is relatively accessible to the enzyme; lysozyme is effective against Gram negative bacteria only after the outer membrane has been compromised.