Antibacterial activity in bovine lactoferrin-derived peptides.
Several peptides sharing high sequence homology with lactoferricin B (Lf-cin B) were generated from bovine lactoferrin (Lf) with recombinant chymosin. Two peptides were copurified, one identical to Lf-cin B and another differing from Lf-cin B by the inclusion of a C-terminal alanine (lactoferricin). Two other peptides were copurified from chymosin-hydrolyzed Lf, one differing from Lf-cin B by the inclusion of C-terminal alanyl-leucine and the other being a heterodimer linked by a disulfide bond. These peptides were isolated in a single step from chymosin-hydrolyzed Lf by membrane ion-exchange chromatography and were purified by reverse-phase high-pressure liquid chromatography (HPLC). They were characterized by N-terminal Edman sequencing, mass spectrometry, and antibacterial activity determination. Pure lactoferricin, prepared from pepsin-hydrolyzed Lf, was purified by standard chromatography techniques. This peptide was analyzed against a number of gram-positive and gram-negative bacteria before and after reduction of its disulfide bond or cleavage after its single methionine residue and was found to inhibit the growth of all the test bacteria at a concentration of 8 microM or less. Subfragments of lactoferricin were isolated from reduced and cleaved peptide by reverse-phase HPLC. Subfragment 1 (residues 1 to 10) was active against most of the test microorganisms at concentrations of 10 to 50 microM. Subfragment 2 (residues 11 to 26) was active against only a few microorganisms at concentrations up to 100 microM. These antibacterial studies indicate that the activity of lactoferricin is mainly, but not wholly, due to its N-terminal region.
Hoek
K S
KS
Centre for Food Technology, Department of Primary Industries Queensland, Hamilton, Australia. hoek@biosci.uq.edu.au
Milne
J M
JM
Grieve
P A
PA
Dionysius
D A
DA
Smith
R
R
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D002417:Cattle; D012085:Chymosin; D003488:Cyanogen Bromide; D006863:Hydrogen-Ion Concentration; D007781:Lactoferrin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D008623:Mercaptoethanol; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D010446:Peptide Fragments; C082171:lactoferricin B; D008623:Mercaptoethanol; D007781:Lactoferrin; D012085:Chymosin; D003488:Cyanogen Bromide