preferred_name: homogentisate + O2 <=> 4-maleylacetoacetate + H(+)
preferred_name_lc: homogentisate + o2 <=> 4-maleylacetoacetate + h(+)
label: homogentisate + O2 <=> 4-maleylacetoacetate + H(+)
label_lc: homogentisate + o2 <=> 4-maleylacetoacetate + h(+)