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Isolation of Labile Multi-protein Complexes by in vivo Controlled Cellular Cross-Linking and Immuno-magnetic Affinity Chromatography
Published on: March 9, 2010
Immunological study of complex formation between soluble transferrin receptor and transferrin
1Department of Biochemistry, Moscow State University, Moscow, Russia. kogan@genebee.msu.ru
American Journal of Hematology
|July 27, 2005
Summary
Soluble transferrin receptor (sTfR) in human plasma forms complexes with transferrin (Tf). All sTfR in serum exists as a 2:2 sTfR/Tf complex, with no free sTfR detected.
Area of Science:
- Biochemistry
- Molecular Biology
- Immunology
Background:
- Transferrin receptor (TfR) facilitates cellular iron uptake via transferrin (Tf) binding.
- Soluble transferrin receptor (sTfR) is the extracellular portion of TfR released into circulation.
Purpose of the Study:
- To develop immunofluorescent methods for determining sTfR and sTfR-Tf complexes.
- To investigate the complex formation between isolated sTfR and Tf.
Main Methods:
- Development of immunofluorescent assays using monoclonal antibodies.
- Isolation of sTfR from human plasma.
- Stepwise complex construction and FPLC gel filtration for complex analysis.
Main Results:
- sTfR can bind two Tf molecules sequentially.
- FPLC identified 2:1 (291-kDa) and 2:2 (345-kDa) sTfR/Tf complexes, with isolated sTfR being 237-kDa.
- Serum analysis revealed all sTfR is bound to Tf in a 2:2 complex.
Conclusions:
- sTfR exists exclusively as a 2:2 complex with Tf in human serum.
- The dimeric structure of sTfR and the nature of its binding to Tf in serum warrant further investigation.
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