Manganese transferrin

Crossgrove JS, Allen DD, Bukaveckas BL, Rhineheimer SS, and Yokel RA (2003) Manganese distribution across the blood-brain barrier. I. Evidence for carrier-mediated influx of manganese citrate as well as manganese and manganese transferrin. Neurotoxicology 24 3—13. 

E S R.. Fenton. Transferrin Complexes with Non-Physiological and Toxic Metals, David M. Taylor. Transferrins, Edward N. Baker. Galactose Oxidase, Peter Knowles and Nobutoshi Ito. Chemistry of Aqua Ions of Biological Importance, David T. Richens. From a Structural Perspective Structure and Function of Manganese - Containing Biomolecules, David C. Weatherburn, Index. Volume 3,1996,304 pp. 109.50/ 70.00 ISBN 1-55938-642-8... 

Very little is known about the transport of nickel, manganese and cobalt. Plasma transferrin, conalbumin and citrate have been suggested to serve as carrier ligands. Transferrin is the main transport protein for vanadium in humans, and will transfer vanadium to ferritin. 

Human serum transferrin and chicken ovotransferrin have been reported to bind cobalt, iron, copper, zinc, and manganese. The iron complex is red with an absorption maximum at 465 mp.. Complexes of copper and manganese are yellow. Ulmer and Vallee (128) formed a complex with Mn3+ by standing for 12 hours while Inman (68) formed a complex by addition of hydrogen peroxide to a mixture of Mn2+ and the transferrins. Absorption spectra for three of the colored complexes of human serum transferrin are given in Fig. 5. Extinction coefficients are listed in Table 9. 

Takeda A, Devenyi A, Connor JR (1998) Evidence for non-transferrin-mediated uptake and release of iron and manganese in glial cell cultures from hypotransferrinemic mice. J Neurosci Res 51 454-462... 

Because most of the first transition series elements are essential in biological systems there is considerable interest in the possibility that transferrins may be involved in their binding and translocation. This is certainly a distinct possibility, because neither transferrin nor lactoferrin is more than 30% saturated with iron in body fluids. There is as yet little hard evidence, however. Transferrin has been reported to be the main carrier for manganese in blood (158), just as lactoferrin is in milk (25), and thermodynamic studies suggest that transferrin is also capable of competing with serum albumin for zinc under the... 

Inman first showed that trivalent manganese formed a complex with transferrins by adding hydrogen peroxide to a mixture of Mn2+ and the apoenzyme (118). Displacement studies revealed that the order of binding for both the human serum enzyme and ovotransferrin was Fe3+ > Mn3+ > Cu2+. The Mn complex displayed a distinctive visible band maximum at 429 nm. Further studies of the Mn-containing protein by... 

Excitation of the visible absorption band of the manganese-containing proteins of human serum transferrin and ovotransferrin with an argon laser results in resonance-enhanced Raman bands at 1603, 1501,1264, 1173, and 752 cm1 and 1600,1500, 1236, 1171, and 752 cm-1, respectively (104). These frequencies are almost identical to those enhanced in the iron analog, demonstrating that the Mn probably occupies the iron-binding sites. All of these enhanced bands were assigned to phenolic vibrational modes. Similar studies with human... 

Transferrin is a reversible iron-binding protein used in vertebrate iron-transport see Iron Proteins for Storage Transport their Synthetic Analogs). Manganese will bind to transferrin in vitro to form a Mn -transferrin complex. Transferrin appears to bind the majority of the serum Mn and may be important in Mn transport. 

Transferrin is mainly synthesized in the hepatocytes. There are about 20 known variants. Iron is transported by transferrin (approx. 30% of transferrin is saturated with iron). With the help of a membrane receptor, the iron-transferrin complex is taken up and released in the liver cell, where it is immediately bound (because of its toxicity) to ferritin. The liver cells take up iron predominantly from transferrin, to a lesser degree also from haptoglobin, haemopexin, lactoferrin and circulating ferrin. Transferrin, which is mainly formed in the hepatocytes, may also bind and transport, in decreasing order, chromium, copper, manganese, cobalt, cadmium, zinc and nickel. The half-life of transferrin is 1 - 2 hours, which is very short in view of its total blood concentration of 3-4 mg. Approximately 0.4 g ferritin iron is stored in the liver. In the case of transferrin deficiency, its bacteriostatic and fungistatic effects are also reduced. Transferrin without iron saturation is known as apo-transferrin. (31, 66, 67)... 

The liver contains 24 pmol/kg BW, which is equivalent to approximately 10% of the body s manganese depot (0.2-0.36 mmol). It is bound to transferrin for transport in the blood. (66)... 

Once absorbed, manganese is transported in portal blood to the liver bound to albumin and then exported to other tissue bound to transferrin and possibly to 2 macroglob-uhn. Excretion of manganese is primarily via bile into feces, with urine output being very low and not sensitive to dietary intake. ... 

Transferrin is one of the proteins responsible for binding and transporting both iron and manganese throughout the body. One study (Vahlquist et al. 1975) reported no correlation between infant cord blood and maternal blood transferrin levels. The same study reported an increase in plasma transferrin from 1.68-H/-0.60 mg/mL in blood from infants at 6 weeks of age, to a peak of 2.60+1-0.21 mg/mL at 10 months, with values stabilizing at these adult levels throughout 16 years of age. The authors did not comment as to the statistical difference, if any, of these values. 

Suarez N, Walum E, Eriksson H. 1995. Cellular neurotoxicity of trivalent manganese bound to transferrin or pyrophosphate studied in human neuroblastoma (SH-SY5Y) cell cultures. Toxicol in Vitro 9 717-721. 

Influence of transferrin on manganese uptake in rat brain. J Neurosd Res 59 542—552. 

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