A kinetic study of the role of band 3 anion transport protein in the transport of salicylic acid and other hydroxybenzoic acids across the human erythrocyte membrane.

The mechanism of transport of salicylic acid and five other hydroxybenzoic acids across the human erythrocyte membrane was investigated. The specific anion transport inhibitor, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, reduced but did not totally abolish transport of these acids. This observation suggests that these acids are transported by two parallel processes, one involving the band 3 anion transport protein channel and the other probably involving passive diffusion of the un-ionized molecule. The activation energies for membrane transport were large (99-127 kJ.mol-1), an observation that is consistent with the rate-limiting step for anion transport being the conformational change of the band 3 anion transport protein.