Selenoprotein P
In molecular biology, the protein domain selenoprotein P is the only known eukaryotic selenoprotein that contains multiple selenocysteine residues. It is a secreted glycoprotein, often found in the plasma. Its precise function remains to be elucidated; however, it is thought to have antioxidant properties. This particular protein contains two domains: the C terminal and N terminal domain. The N-terminal domain is larger than the C terminal and the N-terminal is thought to be glycosylated. The human version is SEPP1.
Function
SelP may have antioxidant properties. It can attach to epithelial cells, and may protect vascular endothelial cells against peroxynitrite toxicity. The high selenium content of SelP suggests that it may be involved in selenium intercellular transport or storage. The promoter structure of bovine SelP suggests that it may be involved in countering heavy metal intoxication, and may also have a developmental function.Structure
The N-terminal region always contains one Sec residue, and this is separated from the C-terminal region by a histidine-rich sequence. The large number of Sec residues in the C-terminal portion of SelP suggests that it may be involved in selenium transport or storage. However, it is also possible that this region has a redox function.N terminal domain
Function
N-terminal domain allows conservation of whole body seleniumand appears to supply selenium to the kidney.
Structure
The structure of the N-terminal domain is larger and contains less Selenium. However it is thought to be heavily glycosylated.C terminal domain
Function
The function of the C-terminal domain is known to be vital for maintaining levels of selenium in brain and testis tissue but not for the maintenanceof whole-body selenium.