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