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Multiple forms of selenoprotein P in rat plasma
H S Chittum1, S Himeno, K E Hill
1Department of Medicine, Vanderbilt University, Nashville, Tennessee 37232-2279, USA.
Archives of Biochemistry and Biophysics
|January 1, 1996
Summary
Researchers identified five distinct forms of rat selenoprotein P, revealing at least two isoforms based on size and heparin-binding properties. This study advances our understanding of selenoprotein P heterogeneity.
Area of Science:
- Biochemistry
- Proteomics
- Molecular Biology
Background:
- Selenoprotein P is a key selenium-carrying protein in plasma.
- Previous studies suggested potential heterogeneity of selenoprotein P.
Purpose of the Study:
- To investigate the heterogeneity of rat plasma selenoprotein P.
- To characterize different forms of selenoprotein P based on size and affinity.
Main Methods:
- Immunoaffinity purification of rat selenoprotein P.
- Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).
- Heparin-Sepharose chromatography with pH gradient elution.
- N-terminal amino acid sequencing.
- Phosphorimaging and digoxigenin-based staining.
Main Results:
- SDS-PAGE revealed two major bands at 57 kDa and 45 kDa.
- Heparin-Sepharose chromatography separated 75Se-labeled selenoprotein P into five distinct forms.
- These forms were characterized by different elution profiles and SDS-PAGE migration.
- N-terminal sequencing confirmed all five forms share the same N-terminal sequence.
- All five forms were found to contain carbohydrate moieties.
Conclusions:
- Plasma-derived selenoprotein P exists as at least two isoforms, with distinct 45 kDa and 57 kDa forms.
- Five specific forms of rat selenoprotein P were identified and designated based on elution and size.
- The findings demonstrate significant heterogeneity in selenoprotein P structure and properties.