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