Uroporphyrinogen-III C-methyltransferase

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Uroporphyrinogen-III C-methyltransferase
EC no.
CAS no.125752-76-3
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum

Uroporphyrinogen-III C-methyltransferase (EC, uroporphyrinogen methyltransferase, uroporphyrinogen-III methyltransferase, adenosylmethionine-uroporphyrinogen III methyltransferase, S-adenosyl-L-methionine-dependent uroporphyrinogen III methylase, uroporphyrinogen-III methylase, SirA, CysG, CobA, uroporphyrin-III C-methyltransferase, S-adenosyl-L-methionine:uroporphyrin-III C-methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:uroporphyrinogen-III C-methyltransferase.[1][2][3] This enzyme catalyses the following chemical reaction

2 S-adenosyl-L-methionine + uroporphyrinogen III 2 S-adenosyl-L-homocysteine + precorrin-2 (overall reaction)
(1a) S-adenosyl-L-methionine + uroporphyrinogen III S-adenosyl-L-homocysteine + precorrin-1
(1b) S-adenosyl-L-methionine + precorrin-1 S-adenosyl-L-homocysteine + precorrin-2
uroporphyrinogen III substrate of the enzyme
precorrin-2 product of the enzyme

Uroporphyrinogen-III C-methyltransferase catalyses two methylation reactions. The first reaction converts uroporphyrinogen III into precorrin-1. The second converts precorrin-1 into precorrin-2. These reactions are part of the biosynthetic pathway to cobalamin (vitamin B12) in both anaerobic and aerobic bacteria.

See also[edit]


  1. ^ Warren MJ, Gonzalez MD, Williams HJ, Stolowich NJ, Scott AI (1990). "Uroporphyrinogen-III methylase catalyzes the enzymatic-synthesis of sirohydrochlorin-II and sirohydrochlorin-IV by a clockwise mechanism". J. Am. Chem. Soc. 112: 5343–5345. doi:10.1021/ja00169a048.
  2. ^ Warren MJ, Roessner CA, Santander PJ, Scott AI (February 1990). "The Escherichia coli cysG gene encodes S-adenosylmethionine-dependent uroporphyrinogen III methylase". The Biochemical Journal. 265 (3): 725–9. doi:10.1042/bj2650725. PMC 1133693. PMID 2407234.
  3. ^ Schubert HL, Raux E, Brindley AA, Leech HK, Wilson KS, Hill CP, Warren MJ (May 2002). "The structure of Saccharomyces cerevisiae Met8p, a bifunctional dehydrogenase and ferrochelatase". The EMBO Journal. 21 (9): 2068–75. doi:10.1093/emboj/21.9.2068. PMC 125995. PMID 11980703.

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