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