Transferrin and Lactoferrin

Gutteridge, J.M.C. (1987). Bleomycin-detectable iron in knee-joint synovial fluid from arthritic patients and its relationship to the extracellular activities of caeruloplasmin, transferrin and lactoferrin. Biochem. J. 245, 415-421. 

Monteiro, H.P. and Winterbourne, C.C. (1988). The superoxide-dependent transfer of iron from ferritin to transferrin and lactoferrin. Biochem. J. 256, 923-928. 

FhuA and FepA will prove to be the reference structures for a large group of bacterial outer-membrane transporters that take up bacterial Fe3+-siderophores, Fe3+ released from host transferrin and lactoferrin, haem, and haem released from haemoglobin and haemopexin. It is assumed that all iron sources are transported... 

The majority of Fur-regulated gene products are involved in iron uptake. Genes for transport and biosynthesis of enterobactin have been studied in E. coli K-12 (Earhart, 1996). It is assumed that this system is found in nearly every E. coli strain. Also the ferrichrome transport system seems to have a very broad distribution. The ferric citrate transport system (fee), however, is only present in some E. coli strains and may be part of a pathogenicity island. The aerobactin and yersiniabactin biosynthesis and transport systems are not found in all E. coli strains and are integrated into pathogenicity islands (Schubert et al., 1999). The ability to utilize haem seems also to be a specific pathogenicity-related adaptation. Haem transport systems are used in the animal or human host, where transferrin and lactoferrin create an iron-poor environment for bacteria. 

Transferrin and lactoferrin deprive organisms of the trace quantities of iron needed for metabolism. 

Moshtaghie AA, Skillen AW. 1986. Binding of aluminum to transferrin and lactoferrin. Biochem Soc Trans 14 916-917. 

Kay, C. W. M., Mkami, H. E., Cammack, R., and Evans, R. W. (2007). Pulsed ELDOR determination of the intramolecular distance between the metal binding sites in dicupric human serum transferrin and lactoferrin. J. Am. Chem. Soc. 129, 4868. 

The effect of pH differs for the two sites of transferrin and differs between transferrin and lactoferrin. When titrated with acid, in the absence of chelators, serum transferrin loses iron over the pH range 6.0 to 4.0 release is biphasic (Fig. 28), with iron lost from the more acid-labile N-lobe site first (Section IV.D.l). Lactoferrin, on the other hand, is distinctly more stable in acid, with release occurring 2 pH units lower, over the pH range 4.0 to 2.5, and the two sites losing iron essentially together. 

E27.5 Gallium(III) can bind to transferrin and lactoferrin, and can even be incorporated into ferritin (a biological iron storage ). These enzymes use nitrogen and oxygen donors to bind iron. Since Ga(III) also has a good affinity for the same donors, it can compete with Fe(III) for the binding sites. One major difference between Fe(lll) and Ga(lII) is their redox chemistry. While Fe(Ill) can be reduced to Fe(II), Ga(Ill) cannot. This is an important... 

Transferrin and lactoferrin belong to a family of Fe cation buffer and carrier proteins. X-ray crystallography has shown that both proteins include two distorted octahedral Fe + sites, each of which is coordinated with one aspartate, one histidine, and two tyrosinate residues as well as one exogenous carbonate. Luminescent lanthanides such as Tb + and Eu + cations can be incorporated along with Ee cations into these binding sites to provide water-soluble luminescent lanthanide complexes in sophisticated three-dimensional cages. 

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