Lactoferrin is a 77-78kD metal-binding single-chain glycoprotein found in milk and other exocrine secretions. It is the major protein component of human colostral whey, with concentrations as high as 6mg/ml. Since the human lactoferrin gene has been cloned, overexpression and large scale lactoferrin production are now possible.
A great deal of structural information has been obtained about the lactoferrin molecule. It has been possible to relate this structural information to two striking in vitro properties of lactoferrin, its ability to bind a wide variety of metal ions with extremely high affinity, and its ability to bind to a number of different types of cells.
Lactoferrin is an iron binding protein. It is structurally similar to transferrin, the plasma iron transport protein; but lactoferrin has a much higher affinity for iron (250 fold). It is very abundant in colostrum and small amounts can also be found in tears, saliva, mucous secretions and in the secondary granules of neutrophils. It is made by mucosal epithelium and neutrophils and is released by these cells in response to inflammatory stimuli. Bacterial growth is inhibited by its ability to sequester iron and also permeabilize bacterial cell walls by binding to lipopolysaccharides through its N-terminus. Lactoferrin can inhibit viral infection by binding tightly to the viral envelope protein. This prevents cell-virus fusion by blocking the binding domain. Lactoferrin appears to activate host defense systems in part by stimulating the release of interleukin-8, a neutrophil activator. It may also be involved in antibody and interleukin synthesis, lymphocyte proliferation and complement activation.
Molecular Weight:90kD
Solubility:Very faint orange to pink, clear to slightly hazy
Water (Karl Fischer):≤10%
% Protein (Biuret):≥90%
Storage and Stability:Store at 4ºC. Stable for 12 months after receipt.
