Lactoferrin (Lf - α) is a major constituent 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 - α is also the major Fe binding protein hi milk. Fe bound to Lf - α is available for metabolic use, but the mechanism of Fe release from Lf - α is 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 tune of exposure to and concentration of neuraminidase, and was not due to Lf - α loss or degradation. Readdition of sialic acid to desialylated Lf - α using α - 2, 6 - sialyltransferase restored Fe binding. The results suggest that sialylation - desialylation reactions could play a role in physiologic binding and release of Fe from the very high affinity binding sites of Lf-α.
All Science Journal Classification (ASJC) codes
- Cancer Research