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