Antibacterial activity of anionic peptides produced from tryptic hydrolysate of whey protein.

MM NOE; JA RODRIGUEZ; GR BARREDO VACCHELLI; SA CAMPERI; MA PERILLO; MV NOLAN

Congreso; XLIX Reunión Anual SAB; 2021

Antimicrobial peptides (AMPs) show a broad spectrum of antimicrobial activity against awide range of pathogens, and therefore play an important role in innate host defense. AllAMPs are synthesized as proforms, which are subsequently processed into maturepeptides of various lengths and structures. All the naturally occurring whey proteins havebeen reported to be the source of bioactive peptides when digested enzymatically. Trypticwhey protein hydrolyzate contains different anionic peptides. In the present work weanalyze the antibacterial activity of one of these anionic peptides from β-lactoglobulin, β-Lg 125-135 (TPEVDDEALEK) which has net charge of -4 at pH 7. Antibacterial activitywas expressed as log NC/NI, where NC is the 24 h increase in the number of colonyformingunits without peptide, and NI is the 24 h increase in the number of colonyformingunits with peptide. The growth inhibition in the presence β-Lg125-135 peptide ofat a concentration of 2mM was 0.99 and 0.34 against Staphylococcus aureus ATCC 25923Escherichia coli ATCC 25922 respectively. Usually, antibiotic peptides were described ascationic molecules that interact preferentially with anionic lipid membranes throughelectrostatic interactions. In this case, instead, the β-Lg125-135 peptide was anionic andthe interaction seems to occur through a cationic salt bridge between the peptide and theanionic lipid interface that mimics the microbial cell membrane.