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Plasmin digest of κ-casein as a source of antibacterial peptides

Marjaneh Sedaghati1, Hamid Ezzatpanah1, Masoud Mashhadi Akbar Boojar2

  • 1Department of Food Science and Technology, College of Food Science and Technology, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran.

The Journal of Dairy Research
|March 20, 2014
PubMed

Insights

The plasmin digest of bovine kappa-casein exhibits significant antibacterial properties against pathogenic bacteria like E. coli and S. aureus. Specific peptides, particularly kappa-C3, show potent activity, suggesting potential as a natural food preservative.

Area of Science:

  • Food Science
  • Microbiology
  • Biochemistry

Background:

  • Bovine kappa-casein is a major milk protein.
  • Antimicrobial peptides (AMPs) are crucial for innate immunity and have potential as food preservatives.
  • Enzymatic hydrolysis can generate bioactive peptides from proteins.

Purpose of the Study:

  • To investigate the antibacterial activity of plasmin-hydrolyzed bovine kappa-casein and its fractions.
  • To identify specific antibacterial peptides derived from kappa-casein.
  • To evaluate the potential of these peptides as natural antibacterial agents in the food industry.

Main Methods:

  • Plasmin hydrolysis of bovine kappa-casein.
  • Reverse-phase high-performance liquid chromatography (RP-HPLC) for fraction isolation.
  • Minimum Inhibitory Concentration (MIC) assays against target bacteria (E. coli, S. aureus, L. casei, L. acidophilus).
  • Liquid chromatography-Mass spectrometry (LC-MS) for peptide identification.

Main Results:

  • Three peptides (kC1, kC3, kC4) demonstrated antibacterial activity, with kC3 being the most potent.
  • The intact plasmin digest of kappa-casein showed greater antibacterial potential than its isolated fractions.
  • Gram-positive bacteria were generally more susceptible to the antibacterial effects than Gram-negative bacteria.
  • Antibacterial activity was not directly correlated with peptide charge or hydrophobicity.

Conclusions:

  • Plasmin-hydrolyzed kappa-casein possesses significant antibacterial properties.
  • Specific peptides derived from kappa-casein, like kC3, are effective antimicrobial agents.
  • The findings support the potential use of kappa-casein hydrolysates as natural antibacterial agents in food applications.

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