uroporphyrin-III C-methyltransferase activity https://github.com/geneontology/go-ontology/issues/28199 https://github.com/geneontology/go-ontology/issues/30193 uroporphyrinogen-III methyltransferase activity Catalysis of the reaction: uroporphyrinogen III + 2 S-adenosyl-L-methionine = precorrin-2 + 2 S-adenosyl-L-homocysteine + H+. uroporphyrinogen methyltransferase activity GO:0004851 urogen III methylase activity RHEA:32459 S-adenosyl-L-methionine-dependent uroporphyrinogen III methylase activity uroporphyrinogen-III C-methyltransferase activity S-adenosyl-L-methionine:uroporphyrinogen-III C-methyltransferase activity adenosylmethionine-uroporphyrinogen III methyltransferase activity CysG molecular_function SirA uroporphyrinogen III methylase activity MetaCyc:RXN-13403 S-adenosyl-L-methionine:uroporphyrin-III C-methyltransferase activity SUMT activity EC:2.1.1.107 uroporphyrinogen-III methylase activity CobA C-methyltransferase activity S-adenosylmethionine-dependent methyltransferase activity