Heterogeneity in the human erythrocyte band 3 anion-transporter revealed by Triton X-114 phase partitioning.
Triton X-114 phase partitioning used in conjunction with countercurrent distribution was utilized to examine the phasing properties of the human erythrocyte Band 3 anion-transport protein. Phase partitioning and countercurrent distribution of Band 3 protein followed by electrophoresis and immunoblotting revealed that Band 3 protein possesses biphasic properties with approx. 65% of the Band 3 97,000-Mr species being localized in the detergent phase and 35% isolated in the aqueous phase. The bidirectional phasing of the anion-transporter does not appear to be a result of glycosylation or phosphorylation, since treatment of alkali-washed ghosts with glycosidases or phosphatase respectively did not significantly alter the phasing profiles. Chymotrypsin treatment of erythrocytes followed by the purification of the 60,000-Mr fragment, and exposure of this fragment to phase separation and countercurrent distribution also revealed biphasic partitioning with 70% of the species being isolated in the aqueous phase and 30% in the detergent phase. These data demonstrate that the human erythrocyte Band 3 anion-transport protein is heterogenous by Triton X-114 phase partitioning and that this heterogeneity is preserved in the 60,000-Mr chymotryptic fragment of Band 3 protein.
Swanson
M L
ML
Department of Physiology and Biophysics, University of Iowa, Iowa City 52242.
Keast
R K
RK
Jennings
M L
ML
Pessin
J E
JE
D001457:Anion Exchange Protein 1, Erythrocyte / Q000097:blood*; D002498:Centrifugation; D003377:Countercurrent Distribution; D003902:Detergents; D004910:Erythrocyte Membrane / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D017830:Octoxynol; D010446:Peptide Fragments / Q000032:analysis; D011092:Polyethylene Glycols
D001457:Anion Exchange Protein 1, Erythrocyte; D003902:Detergents; D010446:Peptide Fragments; D011092:Polyethylene Glycols; D017830:Octoxynol; C010615:Nonidet P-40