Abstract: Lactoferrin (LF) is an iron-binding glycoprotein in milk. Bovine lactoferricin (LfcinB) is a peptide having 25 amino acid residue derived from the N-terminal part of BLf . BLf and LfcinB possess a variety biological functions , and it’s broad- spectrum antibacterial activity is knockout . In this experiment, the antibacterial activity of holo-Lf, apo-Lf and LfcinB was studied and compared, and Escherichia coli was used for studying the antimicrobial growth . The results shown that the minimum inhibitory concentration (MIC) of bovine holo-lactoferrin (holo-LFB), bovine apo-lactoferrin (apo-LFB) and lactoferricin (LfcinB) against E.coli is 6mg/ml, 3mg/ml and 15μg/ml and the minimum bactericidal concentration (MBC) of Lfcin against E. coli is 30μg/ml, respectively. The ability of inhibiting E.coli growth enhanced 200 times for apo-LFB and 400 times for holo- LFB after LFB was hydrolysised and puritied.

Key words: bovine lactoferrin, lactoferricinB, MIC, MBC