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Free keywords:
Sphingomyelin; Anion transport; Band 3 protein; Reconstitution, (Erythrocyte membrane); SPH, sphingomyelin; PC, phosphatidylcholine; H2DIDS, 4′-diisothiocyanostilbene-2,2′-disulfonate
Abstract:
The anion transport protein of the human erythrocyte membrane, band 3, was incorporated into unilamellar sphingomyelin vesicles. The vesicles showed a rapid sulfate efflux which could be inhibited by specific inhibitors of the erythrocyte anion transport system. All band 3 molecules contributing to the inhibitor-sensitive flux component were arranged 'right-side-out'. The turnover number of the transport protein for sulfate transport was virtually identical to that in phosphatidylcholine bilayers and around 6 times larger than in human erythrocyte membranes. Thus, in contrast to other claims, sphingomyelin does not inhibit the erythrocyte anion transport system.