Serpins identified as cell growth inhibitors in human plasma.
We have identified a new factor, CFX, in human serum and plasma that inhibits the growth of cultured human and mouse cell lines. CFX was determined to be a negatively charged, hydrophobic glycoprotein, with a native molecular weight of 110-120 kDa and a minimal active subunit of 55 kDa. It is precipitated by 60% ammonium sulfate and is resistant to heat treatment at 100 degrees C for 30 min. CFX was purified from human plasma to a single band on a gel which retained the cell growth inhibitory activity. Amino acid sequence analysis of the CFX band revealed sequences from four human glycoproteins, alpha1-antichymotrypsin, C1-esterase inhibitor, alpha1-antitrypsin, and alpha2-antiplasmin, all members of the superfamily of serpins. Of the four, C1-esterase inhibitor was shown to be the most potent cell growth inhibitor. These results suggest that serpins may play a cell growth inhibitory role in vivo, in addition to their role as protease inhibitors.
Yao
J
J
Department of Pathology and Laboratory Medicine, Boston University School of Medicine, 715 Albany Street, Boston, Massachusetts, 02118, USA.
Baecher-Allan
C M
CM
Sharon
J
J
D002455:Cell Division / Q000187:drug effects*; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D010449:Peptide Mapping; D015843:Serpins / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D014357:Trypsin / Q000737:chemistry; D014407:Tumor Cells, Cultured
D015843:Serpins; D014357:Trypsin