preferred_name: L-histidine(in) + n H(+)(in) => L-histidine(out) + n H(+)(out)
preferred_name_lc: l-histidine(in) + n h(+)(in) => l-histidine(out) + n h(+)(out)
label: L-histidine(in) + n H(+)(in) => L-histidine(out) + n H(+)(out)
label_lc: l-histidine(in) + n h(+)(in) => l-histidine(out) + n h(+)(out)