Lysozyme from chicken egg white

Lysozyme from chicken egg white, is a protein that can show broad spectrum of antibacterial activity against gram positive and gram negative bacteria. Its antimicrobial activity can be enhanced by pretreatment of the target microbial cells with chelating agents like ethylenediaminetetraacetic acid (EDTA).

Lysozyme from chicken egg white may be used as an analytical reference standard for the determination of the analyte in:

• Hard and pasta filata cheeses using reversed-phase high performance liquid chromatography with diode array and fluorimetric detection [(RP-HPLC-DAD) and (RP-HPLC-FLD)].
• Food samples using high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA).

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

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).

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.

1 unit corresponds to the amount of enzyme which decreases the absorbance at 450 nm by 0.001 per minute at pH 7.0 and 25 deg C.

VETRANAL is a registered trademark of Merck KGaA, Darmstadt, Germany