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Isolation of antibacterial hydrolysates from hen egg white lysozyme and identification of antibacterial peptides

Abstract:

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.