Transferrin

TF
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 4X1D, 1A8E, 1A8F, 1B3E, 1BP5, 1BTJ, 1D3K, 1D4N, 1DTG, 1FQE, 1FQF, 1JQF, 1N7W, 1N7X, 1N84, 1OQG, 1OQH, 1RYO, 1SUV, 2HAU, 2HAV, 2O7U, 2O84, 3FGS, 3QYT, 3S9L, 3S9M, 3S9N, 3SKP, 3V83, 3V89, 3V8X, 3VE1, 4H0W, 4X1B, 5DYH
Identifiers
Aliases	TF, PRO1557, PRO2086, TFQTL1, HEL-S-71p, transferrin
External IDs	OMIM: 190000; MGI: 98821; HomoloGene: 68153; GeneCards: TF; OMA:TF - orthologs
Gene location (Human) Chr. Chromosome 3 (human)[1] Band 3q22.1 Start 133,746,040 bp[1] End 133,796,641 bp[1]
Gene location (Mouse) Chr. Chromosome 9 (mouse)[2] Band 9 F1|9 55.03 cM Start 103,081,200 bp[2] End 103,107,643 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in inferior ganglion of vagus nerve corpus callosum superior vestibular nucleus endothelial cell pons middle frontal gyrus inferior olivary nucleus C1 segment ventral tegmental area optic nerve Top expressed in left lobe of liver retinal pigment epithelium human fetus white adipose tissue fetal liver hematopoietic progenitor cell transitional epithelium of urinary bladder utricle yolk sac left lung lobe deep cerebellar nuclei More reference expression data BioGPS More reference expression data
Gene ontology Molecular function ferric iron binding metal ion binding protein binding ferric iron transmembrane transporter activity ferrous iron binding transferrin receptor binding iron chaperone activity Cellular component recycling endosome vesicle HFE-transferrin receptor complex late endosome blood microparticle basal part of cell endocytic vesicle extracellular region cell surface basal plasma membrane extrinsic component of external side of plasma membrane early endosome apical plasma membrane perinuclear region of cytoplasm clathrin-coated pit secretory granule lumen endosome membrane extracellular exosome extracellular space clathrin-coated vesicle membrane cytoplasmic vesicle endoplasmic reticulum lumen Biological process positive regulation of receptor-mediated endocytosis cellular response to iron ion regulation of protein stability transferrin transport iron ion homeostasis platelet degranulation ion transport retina homeostasis iron ion transport cellular iron ion homeostasis membrane organization post-translational protein modification transport iron ion transmembrane transport regulation of iron ion transport Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 7018 22041 Ensembl ENSG00000091513 ENSMUSG00000032554 UniProt P02787 Q921I1 RefSeq (mRNA) NM_001063 NM_001354704 NM_001354703 NM_133977 RefSeq (protein) NP_001054 NP_001341633 NP_001341632 NP_598738 Location (UCSC) Chr 3: 133.75 – 133.8 Mb Chr 9: 103.08 – 103.11 Mb PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Transferrins are glycoproteins found in vertebrates which bind and consequently mediate the transport of iron (Fe) through blood plasma.^[5] They are produced in the liver and contain binding sites for two Fe³⁺ ions.^[6] Human transferrin is encoded by the TF gene and produced as a 76 kDa glycoprotein.^[7][8]

Transferrin glycoproteins bind iron tightly, but reversibly. Although iron bound to transferrin is less than 0.1% (4 mg) of total body iron, it forms the most vital iron pool with the highest rate of turnover (25 mg/24 h). Transferrin has a molecular weight of around 80 kDa and contains two specific high-affinity Fe(III) binding sites. The affinity of transferrin for Fe(III) is extremely high (association constant is 10²⁰ M⁻¹ at pH 7.4)^[9] but decreases progressively with decreasing pH below neutrality. Transferrins are not limited to only binding to iron but also to different metal ions.^[10] These glycoproteins are located in various bodily fluids of vertebrates.^[11][12] Some invertebrates have proteins that act like transferrin found in the hemolymph.^[11][13]

When not bound to iron, transferrin is known as "apotransferrin" (see also apoprotein).