摘要
Lactoferrin(Lf-α)is a major constithent of the secondary granules of neutrophils, and is thought to be involved in bacteriostasis through high affinity binding of plasma Fe required for microbial growth.Lf-αis also the major Fe binding protein in milk. Fe bound to Lf-αis available for metabolic use.but the mechanism of Fe release from Lf-αis unknown.Treatment of human Lf-α with neuraminidase to remove sialic acid residues reduced its ability to bind Fe and caused release of Fe already bound to the protein. Reduction in Fe binding capacity was dependent on time of exposure to and concentration of neuraminidase,and was due to Lf-αloss or degradation. Readdition of sialic arid to desialylated Lf -a using a-2, 6-sialyltransferase restored Fe binding.The results suggest that sialylationdesialylation reactions could play a role in physiologic binding and release of Fe from the very high affinity binding sites of Lf -α.
Lactoferrin(Lf-α)is a major constithent of the secondary granules of neutrophils, and is thought to be involved in bacteriostasis through high affinity binding of plasma Fe required for microbial growth.Lf-αis also the major Fe binding protein in milk. Fe bound to Lf-αis available for metabolic use.but the mechanism of Fe release from Lf-αis unknown.Treatment of human Lf-α with neuraminidase to remove sialic acid residues reduced its ability to bind Fe and caused release of Fe already bound to the protein. Reduction in Fe binding capacity was dependent on time of exposure to and concentration of neuraminidase,and was due to Lf-αloss or degradation. Readdition of sialic arid to desialylated Lf -a using a-2, 6-sialyltransferase restored Fe binding.The results suggest that sialylationdesialylation reactions could play a role in physiologic binding and release of Fe from the very high affinity binding sites of Lf -α.
