This term is obsolete
Consider
GO:0015297,GO:0006810
OBSOLETE. Exchange diffusion of two solutes between the inside and outside of a cell or subcellular compartment, in which movement of one solute down a concentration gradient drives movement of the other solute in the opposite direction. [ GOC:mah ]
Synonyms: solute:solute exchange
This is just here as a test because I lose it