Minimal antimicrobial peptidic sequence from hemoglobin alpha-chain: KYR

► Peptides derived from α 107–141 were antibacterial whatever the bacterial species. ► The most active peptide is the shortest one: α 137–141. ► Shortest the sequence of the peptide is, lowest the MIC is. ► KYR sequence is the minimal antimicrobial sequence from the hemoglobin α-chain. ► These active peptides were able to interact with cellular membrane. Hemoglobin is an animal protein described as a source of biologically active peptides. Peptic digestion of bovine hemoglobin alpha-chain allowed obtaining peptide fractions with antimicrobial activity. These peptides were purified by reverse-phase High-Performance Liquid Chromatography (HPLC) and characterized by mass spectrometry. The minimal inhibitory concentration and mode of action of these peptides were studied against five bacterial strains including Escherichia coli and Salmonella enteritidis as Gram-negative bacteria and Listeria innocua, Micrococcus luteus and Staphylococcus aureus as Gram-positive bacteria. The action aforementioned peptides were studied on artificial membranes as well. The most active peptides resulted to be the short ones. Consequently, the minimal peptidic sequence necessary for the antibacterial activity was clearly determined: KYR.