preferred_name: lactose(out) + H(+)(out) => lactose(in) + H(+)(in)
preferred_name_lc: lactose(out) + h(+)(out) => lactose(in) + h(+)(in)
label: lactose(out) + H(+)(out) => lactose(in) + H(+)(in)
label_lc: lactose(out) + h(+)(out) => lactose(in) + h(+)(in)