preferred_name: Na(+)(in) + NH4(+)(out) => Na(+)(out) + NH4(+)(in)
preferred_name_lc: na(+)(in) + nh4(+)(out) => na(+)(out) + nh4(+)(in)
label: Na(+)(in) + NH4(+)(out) => Na(+)(out) + NH4(+)(in)
label_lc: na(+)(in) + nh4(+)(out) => na(+)(out) + nh4(+)(in)