Method of isolating megakaryocyte stimulatory factor
US4894440A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 17, 1986 |
| Grant date | Jan 16, 1990 |
| Priority date | — |
| Expiry date | Sep 17, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S530/835
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A megakarytocyte stimulatory factor (MSF), purified to homogeneity, is an acidic protein (pI=5.1) with an Mr=15,000 which stimulates PF4-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 exhibits no biologic activity corresponding to other known hemopoietic growth factors, and appears to be specific for the megakaryocyte lineage. In the given examples, MSF was purified to homogeneity (as judged by SDS-PAGE and isoelectric focusing in the presence of 9.2 M urea) from serum-free conditioned medium obtained from cultured human embryonic kidney (HEK) cells, and to near homogeneity from thrombocytopenic plasma. The MSF is isolated by precipitating the MSF with ammonium sulfate at 80% saturation, removing insoluble, non-MSF material and applying the soluble protein to a WGA-Sepharose column, eluting the MSF protein with chitin oligosaccharides, applying the concentrated eluant containing MSF activity to a Biogel P200 column, and chromatographing the eluted MSF fractions on a TSK-G3000 HPLC size exclusion column.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.