Blood transferrin

Gordon, W. G., Groves, M. L. and Basch, J. J. 1963. Bovine milk "red protein" Amino acid composition and comparison with blood transferrin. Biochemistry 2, 817-820. 

An exception to the general theme of pH-dependent receptor-ligand dissociation in the late endosome occurs in the endocytic pathway that delivers transferrin-bound Iron to cells. A major glycoprotein in the blood, transferrin transports Iron to all tissue cells from the liver (the main site of iron... 

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. 

Three forms of folate appear to be transported ia the blood foHc acid, folate loosely bouad to low affinity binder semm proteins (such as albumin, a-macroglobulin, and transferrin), and folate bound to high affinity protein binders. Approximately 5% of total semm folate is being transported by high... 

Other non-haem proteins, distinct from the above iron-sulfur proteins are involved in the roles of iron transport and storage. Iron is absorbed as Fe" in the human duodenum and passes into the blood as the Fe protein, transferrin, The Fe is in a distorted octahedral environment consisting of 1 x N, 3x0 and a chelating carbonate ion which... 

Transferrin (Tf) is a Pj-globulin with a molecular mass of approximately 76 kDa. it is a glycoprotein and is synthesized in the liver. About 20 polymorphic forms of transferrin have been found, it plays a central role in the body s metabolism of iron because it transports iron (2 mol of Fe + per mole of Tf) in the circulation to sites where iron is required, eg, from the gut to the bone marrow and other organs. Approximately 200 billion red blood cells (about 20 mL) are catabolized per day, releasing about 25 mg of iron into the body—most of which will be transported by transferrin. 

Decreased red blood cell (RBC) count, hemoglobin (Hgb) and hematocrit (Hct) iron metabolism may also be altered [iron level, total iron binding capacity (TIBC), serum ferritin level, and transferrin saturation (TSAT)]. Erythropoietin levels are not routinely monitored and are generally normal to low. Urine positive for albumin or protein. 

Figure 8.1 Body iron stores and daily iron exchange. The figure shows a schematic representation of the routes of iron movement in normal adult male subjects. The plasma iron pool is about 4 mg (transferrin-bound iron and non-transferrin-bound iron), although the daily turnover is over 30 mg. The iron in parenchymal tissues is largely haem (in muscle) and ferritin/haemosiderin (in hepatic parenchymal cells). Dotted arrows represent iron loss through loss of epithelial cells in the gut or through blood loss. Numbers are in mg/day. Transferrin-Tf haemosiderin - hs MPS - mononuclear phagocytic system, including macrophages in spleen and Kupffer cells in liver.

Ogris M, Brunner S, Schuller S, Kircheis R, Wagner E (1999) PEGylated DNA/transferrin-PEI complexes reduced interaction with blood components, extended circulation in blood and potential for systemic gene delivery. Gene Ther 6 595-605... 

Walus, L.R., Pardridge, W.M., Starzyk, R.M., and Friden, P.M. (1996) Enhanced uptake of rsCD4 across the rodent and primate blood-brain barrier after conjugation to anti-transferrin receptor antibodies. J. Pharmacol. Exp. Ther. 277, 1067. 

Zhang, Y., and Pardridge, W.M. (2005) Delivery of b-Galactosidase to mouse brain via the blood-brain barrier transferrin receptor./. Pharmacol. Exp. Therapeut. 313, 1075-1081. 

Transferrin is an iron carrier protein that acts as a trophic survival factor for neurons, astrocytes and OLs. As the blood-brain barrier becomes established during development, neural cells become dependent on transferrin produced by OLs and choroid plexus epithelial cells (Fig. 25-14). OLs are the major source of transferrin in the CNS. This suggests an important function for OLs in... 

Transferrin 8-9 Binds iron in plasma and transports iron to bone Iron deficiency, pregnancy, hypoxia, chronic blood loss, estrogens Chronic infection, cirrhosis, burns, enteropathies, nephrotic syndrome, cortisone, testosterone... 

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