lactotransferrin

Lactotransferrin, also known as lactoferrin, is a glycoprotein of the transferrin family found in milk and various secretions. In humans, it is encoded by the LTF gene. It is particularly abundant in colostrum and mature milk but is also present in tears, saliva, nasal mucosa, bile, synovial fluid, and neutrophil granules. Levels vary with species, age, pregnancy, and lactation.

Structure: Lactotransferrin is a single polypeptide chain of about 700 amino acids, with a molecular mass of about 78 kDa. It contains two homologous lobes (N and C) forming a bilobal structure, each capable of binding a ferric iron ion in the presence of a carbonate anion. Iron binding is reversible and influences its antimicrobial activity.

Function: The protein sequesters iron, limiting bacterial growth, and exhibits direct antimicrobial effects against bacteria, fungi, and viruses. It can modulate immune responses, bind to bacterial surfaces and lipopolysaccharide, and interact with host cell receptors, promoting anti-inflammatory and immunomodulatory actions. Proteolytic cleavage generates lactoferricin, a small peptide with potent antimicrobial activity.

Clinical and commercial context: Lactotransferrin is used as a functional ingredient in some infant formulas and dietary supplements, often derived from bovine milk or produced recombinantly. It is considered safe for most uses, though dairy-derived proteins can trigger allergies in susceptible individuals. Research continues into therapeutic applications for infections, inflammatory diseases, and wound healing.