1. Rat and rabbit erythrocyte plasma-membrane proteins were solubilized with decanoyl-N-methylglucamide and reconstituted into liposomes. The procedure includes detergent removal by gel filtration, followed by a freeze-thaw step. 2. The rate of [1-14C]pyruvate uptake into these vesicles was inhibited by approx. 70% by alpha-cyano-4-hydroxycinnamate and p-chloromercuribenzenesulphonate. The extent of uptake at equilibrium was not affected by the presence of these inhibitors, but was dependent on the osmolarity of the suspending medium. 3. Reconstituted bovine erythrocyte membranes, which have no lactate carrier, showed a much slower time course of pyruvate uptake, with no inhibitor-sensitive component. 4. L- but not D-lactate competed for alpha-cyano-4-hydroxycinnamate-sensitive [1-14C]pyruvate uptake.
