preferred_name: Ca(2+)(in) + Na(+)(out) <=> Ca(2+)(out) + Na(+)(in)
preferred_name_lc: ca(2+)(in) + na(+)(out) <=> ca(2+)(out) + na(+)(in)
label: Ca(2+)(in) + Na(+)(out) <=> Ca(2+)(out) + Na(+)(in)
label_lc: ca(2+)(in) + na(+)(out) <=> ca(2+)(out) + na(+)(in)