Identification of selenoprotein P fragments as a cell-death inhibitory factor.
Megakaryoblastoma (Dami cells) cultured in a serum-free medium containing albumin, proliferated for three days but died on the fourth day. This cell death was not observed when human plasma was added, suggesting that human plasma contains a cell-death inhibitory factor. In order to identify this factor, we purified it from human plasma. N-terminal amino acid sequence analysis revealed that this factor is a mixture of C-terminal fragments of selenoprotein P, a major selenocysteine-containing protein in plasma. The specific activity (unit per pmol of selenium) of selenoprotein P fragments protein was 15-fold and 1900-fold higher than that of the full-length SeP and sodium selenite, respectively.
Hirashima
Masaki
M
The Chemo-Sero-Therapeutic Research Institute, Kawabe, Kyokushi, Kikuchi-gun, Kumamoto 869-1298, Japan.
Naruse
Takeshi
T
Maeda
Hiroaki
H
Nozaki
Chikateru
C
Saito
Yoshiro
Y
Takahashi
Kazuhiko
K
D000595:Amino Acid Sequence; D000975:Antioxidants / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D016895:Culture Media, Serum-Free; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification* / Q000494:pharmacology; D010949:Plasma / Q000737:chemistry; D011506:Proteins / Q000302:isolation & purification* / Q000494:pharmacology; D012643:Selenium / Q000494:pharmacology; D051149:Selenoprotein P; D051140:Selenoproteins; D014407:Tumor Cells, Cultured
D000975:Antioxidants; D016895:Culture Media, Serum-Free; D010446:Peptide Fragments; D011506:Proteins; D051149:Selenoprotein P; D051140:Selenoproteins; D012643:Selenium