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