| Autor: |
Tayrien, G., Rosenberg, R.D. |
| Zdroj: |
Journal of Biological Chemistry; March 1987, Vol. 262 Issue: 7 p3262-3268, 7p |
| Abstrakt: |
Megakaryocyte stimulatory factor (MSF) has been purified to homogeneity (7.5 × 10(5)-fold) from serum-free conditioned medium obtained from cultured human embryonic kidney cells and to near homogeneity (1.44 × 10(7)-fold) from thrombocytopenic rabbit plasma. MSF activity from either source was assayed by its ability to enhance the rate of synthesis of platelet factor 4-like proteins in a rat promegakaryoblast cell line. The 125I-labeled factor prepared from human embryonic kidney cell conditioned medium is homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing in the presence of 9.2 M urea. MSF obtained from the above source is an acidic protein (pI = 5.1) with an Mr = 15,000 which stimulates platelet factor 4-like protein synthesis in rat promegakaryoblast cells by as much as 7-fold, and exhibits half-maximal activity at a concentration of 0.8 pM. MSF was also purified from thrombocytopenic rabbit plasma by a nearly identical isolation procedure, and 125I-labeled factor prepared from this source also possessed an Mr = 15,000. MSF exhibited no biologic activity corresponding to other known hemopoietic growth factors, and appears to be specific for the megakaryocyte lineage. |
| Databáze: |
Supplemental Index |
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