The Synergistic Antibacterial Properties of Glycinin Basic Peptide against Bacteria via Membrane Damage and Inactivation of Enzymes

摘要

This study investigated the antibacterial properties of glycinin basic peptide (GBP), a natural antibacterial component from soybean protein, against Staphylococcus aureus (S. aureus). The minimum inhibitory and bactericidal concentrations of GBP against S. aureus were 0.2mg/mL and 0.8mg/mL, respectively. Flow cytometry analysis manifested that GBP decreased the number of intact and normal cells. Higher concentrations of GBP induced more severe damage of the bacterial membrane; the maximal percentage of injured and dead cells was 93.8% with 0.8mg/mL GBP. Electron microscopy imaging visually showed the morphological damage of S. aureus by GBP. Intracellular K+ leakage and the membrane depolarization of S. aureus further verified that GBP could destroy the bacterial membrane. Moreover, GBP decreased the activity of nonspecific esterase and ATPase of S. aureus in a concentration-dependent manner. These results demonstrated that GBP exhibited antibacterial properties against S. aureus via synergistic actions of damage to the cell membrane and inactivation of metabolic enzymes.