Antibacterial activity in bovine lactoferrin-derived peptides

Area of Science:

• Biochemistry
• Microbiology
• Peptide Science

Background:

• Bovine lactoferrin (Lf) is a known source of antimicrobial peptides.
• Lactoferricin B (Lf-cin B) is a well-characterized antimicrobial peptide derived from Lf.

Purpose of the Study:

• To generate and characterize novel peptides from bovine lactoferrin using recombinant chymosin.
• To determine the antibacterial activity and structure-activity relationships of these peptides, particularly lactoferricin.

Main Methods:

• Enzymatic hydrolysis of bovine Lf with recombinant chymosin.
• Isolation and purification using membrane ion-exchange chromatography and reverse-phase high-pressure liquid chromatography (HPLC).
• Characterization by N-terminal Edman sequencing, mass spectrometry, and antibacterial assays.

Main Results:

• Several Lf-derived peptides were identified, including lactoferricin, which showed high sequence homology to Lf-cin B.
• Lactoferricin demonstrated potent inhibition against Gram-positive and Gram-negative bacteria at concentrations ≤ 8 microM.
• Subfragment 1 (residues 1-10) of lactoferricin was more active than Subfragment 2 (residues 11-26), indicating the N-terminal region's importance.

Conclusions:

• Chymosin-hydrolyzed bovine lactoferrin yields potent antimicrobial peptides.
• Lactoferricin possesses significant broad-spectrum antibacterial activity.
• The N-terminal region of lactoferricin is primarily responsible for its antimicrobial efficacy.