Relation between red cell anion exchange and urea transport.

The new distilbene compound, DCMBT (4,4'-dichloromercuric-2,2,2',2'-bistilbene tetrasulfonic acid) synthesized by Yoon et al. (Biochim. Biophys. Acta 778 (1984) 385-389) was used to study the relation between urea transport and anion exchange in human red cells. DCMBT, which combines properties of both the specific stilbene anion exchange inhibitor, DIDS, and the water and urea transport inhibitor, pCMBS, had previously been shown to inhibit anion transport almost completely and water transport partially. We now report that DCMBT also inhibits urea transport almost completely and that covalent DIDS treatment reverses the inhibition. These observations provide support for the view that a single protein or protein complex modulates the transport of water and urea and the exchange of anions through a common channel.