Antimicrobial peptides released by enzymatic hydrolysis of hen egg white lysozyme.
This work was aimed at the isolation, purification, and characterization of novel antimicrobial peptides from chicken egg white lysozyme hydrolysate, obtained by peptic digestion and subsequent tryptic digestion. The hydrolysate was composed of over 20 small peptides of less than 1000 Da, and had no enzymatic activity. The water-soluble peptide mixture showed bacteriostatic activity against Gram-positive bacteria (Staphylococcus aureus 23-394) and Gram-negative bacteria (Escherichia coli K-12). Two bacteriostatic peptides were purified and sequenced. One peptide, with the sequence Ile-Val-Ser-Asp-Gly-Asp-Gly-Met-Asn-Ala-Trp, inhibited Gram-negative bacteria E. coli K-12 and corresponded to amino acid residues 98-108, which are located in the middle part of the helix-loop-helix. Another novel antimicrobial peptide inhibited S. aureus 23-394 and was determined to have the sequence His-Gly-Leu-Asp-Asn-Tyr-Arg, corresponding to amino acid residues 15-21 of lysozyme. These peptides broadened the antimicrobial activity of lysozyme to include Gram-negative bacteria. The results obtained in this study indicate that lysozyme possesses nonenzymatic bacteriostatic domains in its primary sequence and they are released by proteolytic hydrolysis.
Department of Food Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada. ymine@uoguelph.ca
Yoshinori
Y
Mine
Fupeng
F
Ma
Sophie
S
Lauriau
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000187:drug effects; D006868:Hydrolysis; D008855:Microscopy, Electron, Scanning; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism*; D010434:Pepsin A / Q000378:metabolism; D010446:Peptide Fragments / Q000378:metabolism* / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013211:Staphylococcus aureus / Q000187:drug effects; D014357:Trypsin / Q000378:metabolism
D000900:Anti-Bacterial Agents; D010446:Peptide Fragments; C421864:hen egg lysozyme; D009113:Muramidase; D014357:Trypsin; D010434:Pepsin A