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Lactoferrin

 

An iron-binding protein found in neutrophils and bodily secretions (milk, tears, saliva, bile, etc.), having bactericidal activity, and acting as an inhibitor of colony formation by granulocytes and macrophages.

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Lactotransferrin
Lactoferrin.png
Richardson diagram of recombinant human lactoferrin. Based on PDB 1b0l.
Available structures
1b0l, 1bka, 1cb6, 1dsn, 1eh3, 1fck, 1h43, 1h44, 1h45, 1hse, 1l5t, 1lcf, 1lct, 1lfg, 1lfh, 1lfi, 1lgb, 1n76, 1sqy, 1vfd, 1vfe, 1z6v, 1z6w, 2bjj
Identifiers
Symbols LTF; GIG12; HLF2
External IDs OMIM150210 MGI96837 HomoloGene1754
Orthologs
Species Human Mouse
Entrez 4057 17002
Ensembl ENSG00000012223 ENSMUSG00000032496
UniProt P02788 Q3TP24
RefSeq NM_002343 (mRNA) NM_008522 (mRNA)
NP_002334 (protein) NP_032548 (protein)
Location Chr 3:
46.48 - 46.53 Mb
Chr 9:
110.86 - 110.89 Mb
PubMed search [1] [2]

Lactoferrin (LF), also known as lactotransferrin (LTF), is a globular multifunctional protein with antimicrobial activity (bacteriocide, fungicide) and is part of the innate defense, mainly at mucoses.[1] Lactoferrin is found in milk and many mucosal secretions such as tears and saliva. Lactoferrin is also present in secondary granules of PMN and also is secreted by some acinar cells. Lactoferrin can be purified from milk or produced recombinantly. Human colostrum ("first milk") has the highest concentration, followed by human milk, then cow milk.[1]

Contents

Structure

Lactoferrin belongs to the transferrin family proteins (TF, melanotransferrin, ovotransferin, etc.). Its molecular mass is 80,000 u (80 kDa). It generally contains two bound Fe+3 ions. It contains 4 identical domains, with two surrounding each iron atom.[2]

Function

Lactoferrin's antimicrobial activity is due partly to its high affinity for Fe3+ (ferric state). LF proteolysis produces the small peptides lactoferricin and kaliocin-1 with antimicrobial activity. The combination of iron and lactoferrin in mucosal secretions modulates the ability and aggregation of pathogenic bacteria, and inhibits both bacteria and viruses from binding to host cells. It is also an antifungal agent[citation needed].

Lactoferrin receptors have been found on brush-border cells, PMN, monocytes, macrophages and activated lymphocytes.[3]

Lactoferrin inhibits dendritic cell-mediated HIV-1 transmission by blocking the binding of the HIV protein gp120 to the cellular receptor DC-SIGN, which is a critical binding interaction that never changes regardless of strain.[4]

Genetics

In humans, the lactoferrin gene (LTF) is located on chromosome 3; location: 3q21-q23.[5]

References

  1. ^ a b Sánchez L, Calvo M, Brock JH (May 1992). "Biological role of lactoferrin". Arch. Dis. Child. 67 (5): 657–61. PMID 1599309. 
  2. ^ Baker EN, Baker HM (January 2009). "A structural framework for understanding the multifunctional character of lactoferrin". Biochimie 91 (1): 3–10. doi:10.1016/j.biochi.2008.05.006. PMID 18541155. 
  3. ^ Levay PF, Viljoen M (1995). "Lactoferrin: a general review". Haematologica 80 (3): 252–67. PMID 7672721. 
  4. ^ Groot F, Geijtenbeek TB, Sanders RW, et al. (March 2005). "Lactoferrin prevents dendritic cell-mediated human immunodeficiency virus type 1 transmission by blocking the DC-SIGN--gp120 interaction". J. Virol. 79 (5): 3009–15. doi:10.1128/JVI.79.5.3009-3015.2005. PMID 15709021. 
  5. ^ McCombs JL, Teng CT, Pentecost BT, Magnuson VL, Moore CM, McGill JR (1988). "Chromosomal localization of human lactotransferrin gene (LTF) by in situ hybridization". Cytogenet. Cell Genet. 47 (1-2): 16–7. PMID 3356163. 

Further reading

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Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Lactoferrin" Read more