HETEROGENEITY IN THE HUMAN-ERYTHROCYTE BAND-3 ANION-TRANSPORTER REVEALED BY TRITON-X-114 PHASE PARTITIONING

  • 1 October 1988
    • journal article
    • research article
    • Vol. 255  (1) , 229-234
Abstract
Triton X-114 phase partitioning used in conjuction 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 97000-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 60000-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 heterogeneous by Triton X-114 phase partitioning and that this heterogeneity is preserved in the 60 000-Mr chymotryptic fragment of Band 3 protein.