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ec00680                     Pathway                                

Methane metabolism
Methane is metabolized principally by methanotrophs and methanogens in the global carbon cycle. Methanotrophs consume methane as the only source of carbon, while methanogens produce methane as a metabolic byproduct. Methylotrophs, which are microorganisms that can obtain energy for growth by oxidizing one-carbon compounds, such as methanol and methane, are situated between methanotrophs and methanogens. Methanogens can obtain energy for growth by converting a limited number of substrates to methane under anaerobic conditions. Three types of methanogenic pathways are known: CO2 to methane [MD:M00567], methanol to methane [MD:M00356], and acetate to methane [MD:M00357]. Methanogens use 2-mercaptoethanesulfonate (CoM; coenzyme M) as the terminal methyl carrier in methanogenesis and have four enzymes for CoM biosynthesis [MD:M00358]. Coenzyme B-Coenzyme M heterodisulfide reductase (Hdr), requiring for the final reaction steps of methanogenic pathway, is divided into two types: cytoplasmic HdrABC in most methanogens and membrane-bound HdrED in Methanosarcina species. In methanotrophs and methyltrophs methane is oxidized to form formaldehyde, which is at the diverging point for further oxidation to CO2 for energy source and assimilation for biosynthesis. There are three pathways that convert formaldehyde to C2 or C3 compounds: serine pathway [MD:M00346], ribulose monophosphate pathway [MD:M00345], and xylulose monophosphate pathway [MD:M00344]. The first two pathways are found in prokaryotes and the third is found in yeast. As a special case of methylotrophs, various amines can be used as carbon sources in trimethylamine metabolism [MD:M00563].
Metabolism; Energy metabolism
BRITE hierarchy
Pathway map
ec00680  Methane metabolism

Ortholog table
M00174  Methane oxidation, methanotroph, methane => formaldehyde [PATH:ec00680]
M00344  Formaldehyde assimilation, xylulose monophosphate pathway [PATH:ec00680]
M00345  Formaldehyde assimilation, ribulose monophosphate pathway [PATH:ec00680]
M00346  Formaldehyde assimilation, serine pathway [PATH:ec00680]
M00356  Methanogenesis, methanol => methane [PATH:ec00680]
M00357  Methanogenesis, acetate => methane [PATH:ec00680]
M00358  Coenzyme M biosynthesis [PATH:ec00680]
M00378  F420 biosynthesis [PATH:ec00680]
M00422  Acetyl-CoA pathway, CO2 => acetyl-CoA [PATH:ec00680]
M00563  Methanogenesis, methylamine/dimethylamine/trimethylamine => methane [PATH:ec00680]
M00567  Methanogenesis, CO2 => methane [PATH:ec00680]
M00608  2-Oxocarboxylic acid chain extension, 2-oxoglutarate => 2-oxoadipate => 2-oxopimelate => 2-oxosuberate [PATH:ec00680]
Other DBs
GO: 0015947
C00011  CO2
C00022  Pyruvate
C00024  Acetyl-CoA
C00033  Acetate
C00036  Oxaloacetate
C00037  Glycine
C00048  Glyoxylate
C00058  Formate
C00065  L-Serine
C00067  Formaldehyde
C00074  Phosphoenolpyruvate
C00082  L-Tyrosine
C00085  D-Fructose 6-phosphate
C00101  Tetrahydrofolate
C00111  Glycerone phosphate
C00118  D-Glyceraldehyde 3-phosphate
C00132  Methanol
C00143  5,10-Methylenetetrahydrofolate
C00149  (S)-Malate
C00168  Hydroxypyruvate
C00184  Glycerone
C00197  3-Phospho-D-glycerate
C00199  D-Ribulose 5-phosphate
C00218  Methylamine
C00227  Acetyl phosphate
C00231  D-Xylulose 5-phosphate
C00237  CO
C00258  D-Glycerate
C00322  2-Oxoadipate
C00354  D-Fructose 1,6-bisphosphate
C00483  Tyramine
C00543  Dimethylamine
C00565  Trimethylamine
C00593  Sulfoacetaldehyde
C00631  2-Phospho-D-glycerate
C00862  Methanofuran
C00876  Coenzyme F420
C01001  Formylmethanofuran
C01005  O-Phospho-L-serine
C01031  S-Formylglutathione
C01046  N-Methyl-L-glutamate
C01080  Reduced coenzyme F420
C01104  Trimethylamine N-oxide
C01179  3-(4-Hydroxyphenyl)pyruvate
C01217  5,6,7,8-Tetrahydromethanopterin
C01274  5-Formyl-5,6,7,8-tetrahydromethanopterin
C01438  Methane
C03232  3-Phosphonooxypyruvate
C03576  Coenzyme M
C03920  2-(Methylthio)ethanesulfonate
C04330  5,10-Methenyltetrahydromethanopterin
C04348  L-Malyl-CoA
C04377  5,10-Methylenetetrahydromethanopterin
C04488  5-Methyl-5,6,7,8-tetrahydromethanopterin
C04628  Coenzyme B
C04732  5-Amino-6-(1-D-ribitylamino)uracil
C04832  Coenzyme M 7-mercaptoheptanoylthreonine-phosphate heterodisulfide
C05528  3-Sulfopyruvate
C06019  D-arabino-Hex-3-ulose 6-phosphate
C11536  (2R)-O-Phospho-3-sulfolactate
C11537  (2R)-3-Sulfolactate
C14180  S-(Hydroxymethyl)glutathione
C16583  (R)-(Homo)2-citrate
C16588  2-Oxopimelate
C16589  2-Oxosuberate
C16590  7-Oxoheptanoic acid
C16593  7-Mercaptoheptanoic acid
C16594  7-Mercaptoheptanoylthreonine
C16597  (-)-threo-Iso(homo)2-citrate
C16598  (R)-(Homo)3-citrate
C16600  (-)-threo-Iso(homo)3-citrate
C19151  Coenzyme F420-3
C19152  Coenzyme F420-1
C19153  Coenzyme F420-0
C19154  7,8-Didemethyl-8-hydroxy-5-deazariboflavin
C19155  (2S)-Lactyl-2-diphospho-5'-guanosine
C19156  (2S)-2-Phospholactate
C20581  cis-(Homo)2-aconitate
C20582  cis-(Homo)3-aconitate
C20926  gamma-Glutamyltyramine
C20954  (5-Formylfuran-3-yl)methyl phosphate
C21068  [5-(Aminomethyl)furan-3-yl]methyl phosphate
C21069  [5-(Aminomethyl)furan-3-yl]methyl diphosphate
C21070  (4-{4-[2-(gamma-L-Glutamylamino)ethyl]phenoxymethyl}furan-2-yl)methanamine
Graham DE, Xu H, White RH
Identification of coenzyme M biosynthetic phosphosulfolactate synthase: a new family of sulfonate-biosynthesizing enzymes.
J Biol Chem 277:13421-9 (2002)
Deppenmeier U
The membrane-bound electron transport system of Methanosarcina species.
J Bioenerg Biomembr 36:55-64 (2004)
Hallam SJ, Putnam N, Preston CM, Detter JC, Rokhsar D, Richardson PM, DeLong EF
Reverse methanogenesis: testing the hypothesis with environmental genomics.
Science 305:1457-62 (2004)
Welander PV, Metcalf WW
Loss of the mtr operon in Methanosarcina blocks growth on methanol, but not methanogenesis, and reveals an unknown methanogenic pathway.
Proc Natl Acad Sci U S A 102:10664-9 (2005)
Yurimoto H, Kato N, Sakai Y
Assimilation, dissimilation, and detoxification of formaldehyde, a central metabolic intermediate of methylotrophic metabolism.
Chem Rec 5:367-75 (2005)
Fricke WF, Seedorf H, Henne A, Kruer M, Liesegang H, Hedderich R, Gottschalk G, Thauer RK.
The genome sequence of Methanosphaera stadtmanae reveals why this human intestinal archaeon is restricted to methanol and H2 for methane formation and ATP synthesis.
J Bacteriol 188:642-58 (2006)
Kato N, Yurimoto H, Thauer RK
The physiological role of the ribulose monophosphate pathway in bacteria and archaea.
Biosci Biotechnol Biochem 70:10-21 (2006)
Thauer RK, Kaster AK, Seedorf H, Buckel W, Hedderich R
Methanogenic archaea: ecologically relevant differences in energy conservation.
Nat Rev Microbiol 6:579-91 (2008)
Liffourrena AS, Salvano MA, Lucchesi GI
Pseudomonas putida A ATCC 12633 oxidizes trimethylamine aerobically via two different pathways.
Arch Microbiol 192:471-6 (2010)

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