Enzymatic synthesis of a new antimicrobial peptides for food purposes

M ADARO; A. G.SALINAS IBALEZ; A. ORIGONE; D. VALLES; F. GUZMAN; A. E. VEGA.; S. BARBERIS

Frontiers in Microbiology

Lausanne: Frontiers Media SA

Año: 2023

1664-302x

IGrowing consumer awareness of the potential negative health effects of syntheticantibiotics has prompted the search for more natural preservatives that can improvethe safety and quality of food. In this study we report the enzymatic synthesis ofN-α-[Carbobenzyloxy]-Ile-Gln (Z-IQ) which is the precursor of Ile-Gln (IQ), a newantibacterial dipeptide, using an aqueous–organic biphasic system formed by 50%(v/v) ethyl acetate in 0.1M Tris – HCl buffer pH 8. A partially purified proteolyticextract from the fruits of Solanum granuloso leprosum, named granulosain, provedto be a robust biocatalyst for the synthesis of Z-IQ, eliciting 71± 0.10% maximalpeptide yield in the above described conditions. After cleaving and purifying IQdipeptide, antimicrobial activity was assayed against Staphylococcus aureus ATCC25923, Staphylococcus hominis A17771, and Staphylococcus aureus C00195,and MIC values between 118± 0.01 μg/mL and 133.7± 0.05 μg/mL were obtained.In addition, IQ showed MIC of 82.4± 0.01 μg/mL and 85.0± 0.00 μg/mL againstEscherichia coli ATCC 25922 and Escherichia coli A17683, respectively. IQ didnot show inhibitory activity against single-drug resistance (SDR) strains, such asKlebsiella oxytoca A19438 (SDR) and Pseudomonas aeruginosa C00213 (SDR), andagainst multidrug-resistant Enterococcus faecalis I00125 (MDR). IQ also causedgrowth inhibition of Helicobacter pylori NCTC 11638 and three wild-type H. pyloristrains, which are sensitive to AML, MTZ, LEV and CLA (H. pylori 659), resistant toLEV (H. pylori 661 SDR), and resistant to MTZ (H. pylori 662 SDR). Finally, this studycontributes with a new dipeptide (IQ) that can be used as an antimicrobial agent forfood preservation or as a safe ingredient of functional foods.