Isolation from fetal bovine serum of an apolipoprotein-H-like protein which inhibits thymidine incorporation in fetal calf erythroid cells.
A 46 kDa heparin-binding protein which inhibits thymidine incorporation in cultures of fetal calf liver erythroid cells was isolated from fetal bovine serum by affinity chromatography on heparin-Sepharose, ion-exchange chromatography, gel filtration and reversed-phase h.p.l.c. The N-terminal sequence of the first 22 amino acids showed 81% identity with the published sequence of human apolipoprotein H. The isolated protein inhibited thymidine incorporation with an ED50 (concn. producing 50% of maximal effect) of 36 nM. A 100% inhibition of thymidine incorporation and a 40% decrease in cell numbers in cultures of fetal calf erythroid cells were observed at a protein concentration of 840 nM. No effects could be seen in cultures of 3T3 cells used as controls. Human apolipoprotein H had no inhibitory activity in any of the cell cultures tested, suggesting a species-specificity or a different structure or function for the bovine heparin-binding protein.
Li
Q G
QG
Endocrine Laboratory, Royal Victoria Hospital, Montreal, Canada.
Blacher
R
R
Esch
F
F
Congote
L F
LF
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004912:Erythrocytes / Q000378:metabolism*; D005312:Fetal Blood / Q000032:analysis / Q000166:cytology; D006023:Glycoproteins / Q000097:blood* / Q000494:pharmacology; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D012689:Sequence Homology, Nucleic Acid; D013936:Thymidine / Q000097:blood*; D053482:beta 2-Glycoprotein I
D006023:Glycoproteins; D053482:beta 2-Glycoprotein I; D013936:Thymidine