uroporphyrinogen III + 2 S-adenosyl-L-methionine = precorrin-2 + 2 S-adenosyl-L-homocysteine + H(+)
uroporphyrinogen iii + 2 s-adenosyl-l-methionine = precorrin-2 + 2 s-adenosyl-l-homocysteine + h(+)
"uroporphyrin-III C-methyltransferase"
"uroporphyrin-iii c-methyltransferase"