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Published on: September 30, 2011
Purification of selenoprotein Ph from human plasma
1Fachrichtung Medizinische Biochemie, Universität des Saarlandes, Homburg/Saar, Fed. Rep. of Germany.
Journal of Trace Elements and Electrolytes in Health and Disease
|December 1, 1993
Summary
Researchers purified human selenoprotein Ph, a key selenium-binding protein in plasma. This protein accounts for most plasma selenium, with purification revealing its microheterogeneity and potential glycoprotein nature.
Area of Science:
- Biochemistry
- Proteomics
- Human Physiology
Background:
- Human plasma contains three primary selenium-binding proteins: glutathione peroxidase (GSH-Px-P), albumin, and selenoprotein Ph.
- Selenoprotein Ph is the human counterpart to rat selenoprotein P and plays a significant role in selenium transport and metabolism.
Purpose of the Study:
- To isolate and characterize human selenoprotein Ph from plasma.
- To determine the purification yield and identify the molecular properties of selenoprotein Ph.
Main Methods:
- Heparin Sepharose chromatography for protein separation.
- Multi-step purification procedure achieving 2588-fold enrichment.
- SDS-PAGE and Isoelectric Focusing (IEF) for analyzing protein purity and heterogeneity.
- Gel filtration chromatography (Fraktogel HW 55, Sephacryl S-200 HR) for molecular mass determination.
Main Results:
- Selenoprotein Ph constitutes 60-70% of total plasma selenium, significantly more than GSH-Px-P and albumin (approx. 15% each).
- Purified selenoprotein Ph exhibited a selenium-containing band on SDS-PAGE between 54-67 kDa (peak at 63 kDa), with microheterogeneity potentially due to its glycoprotein nature.
- Native molecular mass estimations varied (65-89 kDa) depending on the gel filtration matrix, suggesting matrix interactions.
Conclusions:
- A robust purification strategy for human selenoprotein Ph was established.
- The study highlights the significant abundance of selenoprotein Ph in human plasma and its complex molecular characteristics.
- Further investigation is warranted to understand the implications of selenoprotein Ph's microheterogeneity and potential matrix interactions.
