. "Catalysis of the reaction: 2 S-adenosyl-L-methionine + uroporphyrin III = 2 S-adenosyl-L-homocysteine + precorrin-2." . . . "uroporphyrin-III C-methyltransferase activity" . "SirA" . "CysG" . "adenosylmethionine-uroporphyrinogen III methyltransferase activity" . "CobA" . "S-adenosyl-L-methionine-dependent uroporphyrinogen III methylase activity" . "S-adenosyl-L-methionine:uroporphyrin-III C-methyltransferase activity" . "S-adenosyl-L-methionine:uroporphyrinogen-III C-methyltransferase activity" . "SUMT activity" . "urogen III methylase activity" . "uroporphyrinogen III methylase activity" . "uroporphyrinogen methyltransferase activity" . "uroporphyrinogen-III C-methyltransferase activity" . "uroporphyrinogen-III methylase activity" . "uroporphyrinogen-III methyltransferase activity" . . .