Solubilization and characterization of erythropoietin receptor from transplantable mouse erythroblastic leukemic cells.

Functional erythropoietin (Ep) receptor (Ep-R) on transplantable mouse leukemic cells was solubilized by 3[(3-cholamidopropyl)dimethyl ammonio]-1-propanesulfate (CHAPS). An assay of the solubilized Ep-R was established: (1) radioiodinated Ep was bound to the solubilized Ep-R, (2) Ep.Ep-R complexes were covalently cross-linked, (3) the cross-linked products were selectively precipitated by polyethylene glycol, (4) the products were separated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and (5) the Ep.Ep-R cross-linked products were measured. Optimal conditions to yield the cross-linked products and to stabilize the solubilized Ep-R were found. The solubilized Ep-R had properties similar to those of Ep-R on the membrane with respect to binding with Ep and the cross-linked products. These results would be exploited to allow purification of Ep-R.