Application

Enzyme breaks down the cell walls of bacteria; used to prepare spheroplasts.

Lysozyme from chicken egg white has been used:as a standard in small-angle neutron scattering experiments and infrared absorbance spectroscopyas a constituent of cell lysis bufferin protein crystallization experiments

Biochem/physiol Actions

Lysozyme hydrolyzes β(1→4) linkages between N-acetylmuramic acid and N-acetyl-D-glucosamine residues in peptidoglycan and between N-acetyl-D-glucosamine residues in chitodextrin. Gram-positive cells are quite susceptible to this hydrolysis as their cell walls have a high proportion of peptidoglycan. Gram-negative bacteria are less susceptible due to the presence of an outer membrane and a lower proportion of peptidoglycan. However, these cells may be hydrolyzed in the presence of EDTA that chelates metal ions in the outer bacterial membrane.The enzyme is active over a broad pH range (6.0 to 9.0). At pH 6.2, maximal activity is observed over a wider range of ionic strengths (0.02 to 0.100 M) than at pH 9.2 (0.01 to 0.06 M).

Other Notes

Suitable for the hydrolysis of bacterial cell walls, mucopolysaccharides, mucopolypeptides or chitin; degradability of L. lactis subsp. cremoris H2 cell walls; Review

Unit Definition

1 U corresponds to the amount of enzyme which decreases the absorbance at 450 nm by 0.001 per minute at pH 7.0 and 25°C (Micrococcus luteus, ATCC 4698, as substrate)