General description

Lactoferrin from bovine colostrum corresponds to a molecular weight of 80 kDa. It is a glycosylated protein and belongs to the transferrin family. Bovine lactoferrin has N and C-terminal lobes homologous to human lactoferrin.

Application

Lactoferrin from bovine colostrum has been used as standard protein in sodium dodecyl sulfate (SDS)- polyacrylamide gel electrophoresis (PAGE) for the quantification of IgG samples. It has also been used to test its effect in inducing autoimmune pancreatitis.

Lactoferrin from bovine colostrum was used in the characterization of lactoferrin (lf) from colostral whey using anti-lf antibody immunoaffinity chromatography. It was used in the isolation of lactoferrin from bovine colostrum using ultrafiltration coupled with strong cation exchange chromatography.

Biochem/physiol Actions

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.