tokens: Whereas wild - type channels are characterized by pronounced inward rectification and a Cl > thiocyanate > Br > NO ( 3 ) > I > CH ( 3 ) SO ( 3 ) selectivity , G230E exhibits outward rectification at positive potentials and a thiocyanate > NO ( 3 ) > I > Br > Cl > CH ( 3 ) SO ( 3 ) selectivity .