|Superclasses:||Reactions Classified By Conversion Type → Simple Reactions → Chemical Reactions|
|Reactions Classified By Substrate → Small-Molecule Reactions|
EC Number: 126.96.36.199
Enzymes and Genes:
S-adenosylmethionine:2-demethylmenaquinol methyltransferase : menH ( Geobacillus stearothermophilus )
S-adenosylmethionine:2-demethylmenaquinol methyltransferase ( Mycobacterium phlei )
In Pathway: menaquinol-13 biosynthesis
Note that this reaction equation differs from the official Enzyme Commission reaction equation for this EC number, which can be found here .
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
Most BioCyc compounds have been protonated to a reference pH value of 7.3, and some reactions have been computationally balanced for hydrogen by adding free protons. Please see the PGDB Concepts Guide for more information.
Mass balance status: Balanced.
Enzyme Commission Primary Name: demethylmenaquinone methyltransferase
Enzyme Commission Synonyms: S-adenosyl-L-methione-DMK methyltransferase, demethylmenaquinone C-methylase, 2-heptaprenyl-1,4-naphthoquinone methyltransferase, 2-demethylmenaquinone methyltransferase, S-adenosyl-L-methione:2-demethylmenaquinone methyltransferase
Standard Gibbs Free Energy (ΔrG'° in kcal/mol): -20.64 [Latendresse13]
Enzyme Commission Summary:
The enzyme catalyses the last step in menaquinone biosynthesis. It is able to accept substrates with varying polyprenyl side chain length (the chain length is determined by polyprenyl diphosphate synthase) [KoikeTakeshita97]. The enzyme from E. coli also catalyses the conversion of 2-octaprenyl-6-methoxy-1,4-benzoquinone to 2-octaprenyl-3-methyl-6-methoxy-1,4-benzoquinone during the biosynthesis of ubiquinone [Lee97d].
Instance reactions of [S-adenosyl-L-methionine + a demethylmenaquinol → S-adenosyl-L-homocysteine + a menaquinol + H+] (188.8.131.52):
i1: demethylmenaquinol-8 + S-adenosyl-L-methionine → menaquinol-8 + S-adenosyl-L-homocysteine + H+ (184.108.40.206)
i2: demethylmenaquinol-6 + S-adenosyl-L-methionine → menaquinol-6 + S-adenosyl-L-homocysteine + H+ (220.127.116.11)
i3: demethylmenaquinol-7 + S-adenosyl-L-methionine → menaquinol-7 + S-adenosyl-L-homocysteine + H+ (18.104.22.168)
i4: demethylmenaquinol-9 + S-adenosyl-L-methionine → menaquinol-9 + S-adenosyl-L-homocysteine + H+ (22.214.171.124)
i5: demethylmenaquinol-10 + S-adenosyl-L-methionine → menaquinol-10 + S-adenosyl-L-homocysteine + H+ (126.96.36.199)
i6: demethylmenaquinol-11 + S-adenosyl-L-methionine → menaquinol-11 + S-adenosyl-L-homocysteine + H+ (188.8.131.52)
i7: demethylmenaquinol-12 + S-adenosyl-L-methionine → menaquinol-12 + S-adenosyl-L-homocysteine + H+ (184.108.40.206)
i8: demethylmenaquinol-13 + S-adenosyl-L-methionine → menaquinol-13 + S-adenosyl-L-homocysteine + H+ (220.127.116.11)
KoikeTakeshita97: Koike-Takeshita A, Koyama T, Ogura K (1997). "Identification of a novel gene cluster participating in menaquinone (vitamin K2) biosynthesis. Cloning and sequence determination of the 2-heptaprenyl-1,4-naphthoquinone methyltransferase gene of Bacillus stearothermophilus." J Biol Chem 272(19);12380-3. PMID: 9139683
Lee97d: Lee PT, Hsu AY, Ha HT, Clarke CF (1997). "A C-methyltransferase involved in both ubiquinone and menaquinone biosynthesis: isolation and identification of the Escherichia coli ubiE gene." J Bacteriol 1997;179(5);1748-54. PMID: 9045837
Wissenbach92: Wissenbach U, Ternes D, Unden G (1992). "An Escherichia coli mutant containing only demethylmenaquinone, but no menaquinone: effects on fumarate, dimethylsulfoxide, trimethylamine N-oxide and nitrate respiration." Arch Microbiol 1992;158(1);68-73. PMID: 1444716
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