MetaCyc Reaction:

Superclasses: Reactions Classified By Conversion TypeSimple ReactionsChemical ReactionsComposite Reactions
Reactions Classified By SubstrateSmall-Molecule Reactions

EC Number:

Enzymes and Genes:

Escherichia coli K-12 substr. MG1655: uroporphyrin III C-methyltransferase [multifunctional]: cysG
Methanobacterium ivanovii: uroporphyrinogen-III C-methyltransferase: corA
Pseudomonas denitrificans: uroporphyrin-III methyltransferase: cobA
Saccharomyces cerevisiae: uroporphyrinogen-III C-methyltransferaseInferred from experiment: MET1
Salmonella enterica enterica serovar Typhimurium: uroporphyrinogen-III (C7)-methyltransferase [multifunctional]: cysG

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.

Most BioCyc compounds have been protonated to a reference pH value of 7.3. Please see the PGDB Concepts Guide for more information.

Mass balance status: Balanced.

Enzyme Commission Primary Name: uroporphyrinogen-III C-methyltransferase

Enzyme Commission Synonyms: uroporphyrinogen methyltransferase, uroporphyrinogen-III methyltransferase, adenosylmethionine-uroporphyrinogen III methyltransferase, S-adenosyl-L-methionine-dependent uroporphyrinogen III methylase, uroporphyrinogen-III methylase, SirA, CysG, CobA [ambiguous - see EC] SUMT, uroporphyrin-III C-methyltransferase (incorrect), S-adenosyl-L-methionine:uroporphyrin-III C-methyltransferase (incorrect)

Taxonomic Range: Fungi, Bacteria , Archaea

S-adenosyl-L-methionine + uroporphyrinogen-III → S-adenosyl-L-homocysteine + precorrin-1 + H+,
S-adenosyl-L-methionine + precorrin-1 → S-adenosyl-L-homocysteine + precorrin-2

Standard Gibbs Free Energy (ΔrG in kcal/mol): -12.957092Inferred by computational analysis [Latendresse13]

Enzyme Commission Summary:
This reaction is a summary of two individual reactions catalyzed by the enzyme, which are listed above.

This enzyme catalyzes two sequential methylation reactions, the first forming precorrin-1 and the second leading to the formation of precorrin-2. It is the first of three steps leading to the formation of siroheme from uroporphyrinogen III. The second step involves an NAD(+)-dependent dehydrogenation to form sirohydrochlorin from precorrin-2 ( EC and the third step involves the chelation of Fe(2+) to sirohydrochlorin to form siroheme ( EC In Saccharomyces cerevisiae, the last two steps are carried out by a single bifunctional enzyme, Met8p. In some bacteria, steps 1-3 are catalyzed by a single multifunctional protein called CysG, whereas in Bacillus megaterium, three separate enzymes carry out each of the steps, with SirA being responsible for the above reaction. Also involved in the biosynthesis of cobalamin.

Citations: [Schubert02, Warren90]

Gene-Reaction Schematic

Gene-Reaction Schematic

Unification Links: Rhea:32459

Relationship Links: BRENDA:EC:, ENZYME:EC:, IUBMB-ExplorEnz:EC:

Created 03-May-2012 by Caspi R, SRI International


Latendresse13: Latendresse M. (2013). "Computing Gibbs Free Energy of Compounds and Reactions in MetaCyc."

Schubert02: Schubert HL, Raux E, Brindley AA, Leech HK, Wilson KS, Hill CP, Warren MJ (2002). "The structure of Saccharomyces cerevisiae Met8p, a bifunctional dehydrogenase and ferrochelatase." EMBO J 21(9);2068-75. PMID: 11980703

Warren90: Warren MJ, Roessner CA, Santander PJ, Scott AI (1990). "The Escherichia coli cysG gene encodes S-adenosylmethionine-dependent uroporphyrinogen III methylase." Biochem J 265(3);725-9. PMID: 2407234

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.5 on Tue Dec 1, 2015, BIOCYC14B.