Lactoferrin is a globular protein found in milk and many mucosal secretions such as tears. Its molecular atomic mass is 80,000 u (80 kD). This protein belongs to the transferrin family proteins (transferrin, melanotransferrin, ovotransferin, etc.) showing a high affinity by iron (ferric state). Lactoferrin is a multifunctional protein with antimicrobial activity (bacteriocide, fungicide) and is part of the innate defense proteins mainly at mucoses. This protein is present in secondary granules of polymorphonuclear neutrophils (PMN) and also is secreted by some acinar cells. It has been reported lactoferrin-derived peptides (e.g. lactoferricin, kaliocin-1) with antimicrobial activity. Lactoferrin can be purified from milk or produced recombinantly. Human colostrum has the highest concentration, followed by human milk, then cow milk.

[1] Expasy Database, chemical structure