Isolation of Antibacterial Hydrolysates from Hen Egg White Lysozyme and Identification of Antibacterial Peptides

Native and heated hen egg white lysozyme (HEWL) hydrolysates were isolated by hydrolysis with pepsin at pH 2.0 in situ in a cation exchange membrane to isolate and identify antibacterial peptides of the HEWL hydrolysates. Native and heated HEWL was partially hydrolyzed with pepsin at pH 2.0. The fractions were eluted with 5 M ammonia to identify 23 antibacterial peptides using a tandem mass spectrometry. Then, these fractions were eluted with a solution of NaCl 1 M, and seven positively charged peptides f(23-28) YSLGNW, f(122-129) AWIRGCRL, f(123-129) WIRGCRL, f(124-129) IRGCRL, f(82-96) ALLSSDITASVNCAK, f(103-129) VAWRNRCKGTDVQAWIRGCRL, and f(97-123) KIVSDGNGMNAWVAWRNRCKGT were identified using tandem mass spectrometry. Native HEWL hydrolysate presented an enzymatic activity of 23.0%, heated HEWL hydrolysate at pH 6.0 presented a residual enzymatic activity of 22.0%, and heated HEWL hydrolysate at pH 7.0 presented an enzymatic activity of 21.33%. Native and heated HEWL hydrolysate presented antibacterial activity against Escherichia coli and Staphylococcus carnosus. Native HEWL hydrolysate presented a higher enzymatic activity than heated HEWL hydrolysates.