Isolation and characterization of a 37,000-dalton protein associated with the erythrocyte membrane.
We have purified a 37,000-dalton polypeptide (p37) from the red cell membrane that was found in previous studies to undergo a lineage-specific alteration in its membrane association. Our data suggest that p37 associates with the red cell membrane through electrostatic interactions that are resistant to 0.5 M NaCl or 10 mM EDTA. Conditions found to elute p37 from red cell ghosts include H2O at pH 12, 0.1 N NaOH + 1 mM ethanol and 1.0% Triton X-100. p37 was purified substantially from ghosts by Triton X-100 solubilization followed by sequential DEAE-Sephadex and CM-Sephadex chromatography. When p37 was analyzed by two-dimensional gel electrophoresis, a family of isoelectric focusing variants was detected ranging in pI from 7.0 to 7.8. All of the isoelectric focusing variants showed homology to one another when compared serologically with anti-p37 antibodies or by limited peptide mapping using Staphylococcus aureus V8 protease. The isoelectric focusing variants appear to represent distinct, yet related polypeptides rather than degrees of post-translational modifications to a single species, inasmuch as all of the variants are present in anti-p37 immunoprecipitates prepared from in vitro translations programmed with p37 mRNA.
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D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000032:analysis*; D006801:Humans; D007951:Leukemia, Myeloid; D008565:Membrane Proteins / Q000097:blood* / Q000302:isolation & purification; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis
D008565:Membrane Proteins; D010446:Peptide Fragments