Selenoprotein P is a protein that in humans is encoded by the SEPP1 gene.This gene encodes a selenoprotein containing multiple selenocysteine (Sec) residues, which are encoded by the UGA codon that normally signals translation termination. The 3' UTR of selenoprotein genes have a common stem-loop structure, the sec insertion sequence (SECIS), which is necessary for the recognition of UGA as a Sec codon rather than as a stop signal. This selenoprotein is an extracellular glycoprotein, and is unusual in that it contains 10 Sec residues per polypeptide. It is a heparin-binding protein that appears to be associated with endothelial cells, and has been implicated to function as an antioxidant in the extracellular space. Several transcript variants, encoding either the same or different isoform, have been found for this gene. [provided by RefSeq].
Might be responsible for some of the extracellular antioxidant defense properties of selenium or might be involved in the transport of selenium. May supply selenium to tissues such as brain and testis