RESUMO
A peptic hemoglobin hydrolysate was fractioned by a semi-preparative reversed-phase HPLC and some fractions have an antibacterial activity against four bacteria strains: Micrococcus luteus A270, Listeria innocua, Escherichia coli and Salmonella enteritidis. These fractions were analyzed by ESI/MS and ESI/MS/MS, in order to characterize the peptides in these fractions. Each fraction contains at least three peptides and some fractions contain five peptides. All these fractions were purified several times by HPLC to obtain pure peptides. Thirty antibacterial peptides were identified. From the isolated antibacterial peptides, 24 peptides were derived from the alpha chains of hemoglobin and 6 peptides were derived from the beta chains of hemoglobin. The lowest concentration of these peptides (minimum inhibitory concentration (MIC)) necessary to completely inhibit the growth of four bacteria strain was determined. The cell population of all of the tested bacteria species decreased by at least 97% after a 24-h incubation with any of the peptides at the minimum inhibitory concentration.
Assuntos
Antibacterianos/farmacologia , Hemoglobinas/farmacologia , Fragmentos de Peptídeos/farmacologia , Sequência de Aminoácidos , Animais , Antibacterianos/química , Bovinos , Cromatografia Líquida de Alta Pressão , Escherichia coli/efeitos dos fármacos , Hemoglobinas/química , Concentração de Íons de Hidrogênio , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Listeria/efeitos dos fármacos , Espectrometria de Massas , Testes de Sensibilidade Microbiana , Micrococcus luteus/efeitos dos fármacos , Dados de Sequência Molecular , Pepsina A/farmacologia , Fragmentos de Peptídeos/análise , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/isolamento & purificação , Peptídeos/química , Peptídeos/farmacologia , Estrutura Secundária de Proteína , Salmonella enteritidis/efeitos dos fármacosRESUMO
Peptic digestion of bovine hemoglobin at low degree of hydrolysis yields several intermediate peptide fractions after separation by reversed phase HPLC exhibiting antibacterial activity against Micrococcus luteus A270, Listeria innocua, Escherichia coli, and Salmonella enteritidis. From these fractions, four new antibacterial peptides were isolated and analyzed by ESI-MS/MS. Three of these peptides correspond to fragments of the alpha-chain of bovine hemoglobin: alpha107-141, alpha137-141, and alpha133-141, and one peptide to the beta-chain: beta126-145. The minimum inhibitory concentrations (MIC) of these peptides towards the four strains and their hemolytic activity towards bovine erythrocytes were determined.