label: K(+)(in) + 2 hydrogencarbonate(in) + chloride(out) <=> K(+)(out) + 2 hydrogencarbonate(out) + chloride(in)
label_lc: k(+)(in) + 2 hydrogencarbonate(in) + chloride(out) <=> k(+)(out) + 2 hydrogencarbonate(out) + chloride(in)