label: uroporphyrinogen III + 2 S-adenosyl-L-methionine => precorrin-2 + 2 S-adenosyl-L-homocysteine + H(+)
label_lc: uroporphyrinogen iii + 2 s-adenosyl-l-methionine => precorrin-2 + 2 s-adenosyl-l-homocysteine + h(+)